JEE Main & Advanced Physics Thermometry, Calorimetry & Thermal Expansion Question Bank

done Self Evaluation Test - Thermal Properties of Matter Total Questions - 100

• question_answer1)
  If two rods A and B of equal length L, and different areas of cross-section \[{{\operatorname{A}}_{1}}\]and\[{{A}_{2}}\]have one end each at temperature\[{{\operatorname{T}}_{1}}\]and \[{{T}_{2}}\], have equal rates of flow of heat, then
  A)
  \[{{A}_{1}}={{A}_{2}}\] done clear
  B)
   \[\frac{{{A}_{1}}}{{{A}_{2}}}=\frac{{{K}_{1}}}{{{K}_{2}}}\] done clear
  C)
  \[\frac{{{A}_{1}}}{{{A}_{2}}}=\frac{{{K}_{2}}}{{{K}_{1}}}\] done clear
  D)
  \[{{K}_{1}}={{K}_{2}}\] done clear
  View Solution play_arrow

• question_answer2)
  4200 J of work is required for
  A)
  increasing the temperature of 10 g of water through \[10{}^\circ C\] done clear
  B)
  increasing the temperature of 100 g of water through \[10{}^\circ C\] done clear
  C)
  increasing the temperature of 1 kg of water through \[10{}^\circ C\] done clear
  D)
  increasing the temperature of 500 g of water through \[10{}^\circ C\] done clear
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• question_answer3)
  The latent heat of vaporization of a substance is always
  A)
  greater than its latent heat of fusion done clear
  B)
  greater than its latent heat of sublimation done clear
  C)
  equal to its latent heat of sublimation done clear
  D)
  less than its latent heat of fusion done clear
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• question_answer4)
  Six identical conducting rods are joined as shown in figure. Points A and D are maintained at \[200{}^\circ C\]and \[20{}^\circ C\]respectively. The temperature of junction B will be
  A)
  \[120{}^\circ C\] done clear
  B)
  \[100{}^\circ C\] done clear
  C)
  \[140{}^\circ C\] done clear
  D)
  \[80{}^\circ C\] done clear
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• question_answer5)
  500 g of water and 100 g of ice at \[0{}^\circ C\]are in a calorimeter whose water equivalent is 40 g. 10 g of steam at \[100{}^\circ C\] is added to it. Then water in the calorimeter is : (Latent heat of ice =80 cal/g, Latent heat of steam =540 cal/ g)
  A)
  580 g done clear
  B)
  590 g done clear
  C)
  600 g done clear
  D)
  610 g done clear
  View Solution play_arrow

• question_answer6)
  The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively, are\[{{\operatorname{T}}_{2}}\] and \[{{T}_{1}}\]\[({{\operatorname{T}}_{2}}>{{T}_{1}})\]. The rate of heat transfer through the slab, in a steady state is \[\left( \frac{A\left( {{\operatorname{T}}_{2}}>{{T}_{1}} \right)K}{x} \right)f\], with f equal to             
  A)
  \[\frac{2}{3}\] done clear
  B)
  \[\frac{1}{2}\] done clear
  C)
  1 done clear
  D)
  \[\frac{1}{3}\] done clear
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• question_answer7)
  A block of ice at \[-10{}^\circ C\]is slowly heated and converted to steam at \[100{}^\circ C\]. Which of the following curves represents the phenomenon qualitatively                                                    Tricky
  A)
    done clear
  B)
  done clear
  C)
  done clear
  D)
    done clear
  View Solution play_arrow

• question_answer8)
  Assuming no heat losses, the heat released by the condensation of x g of steam at \[100{}^\circ C\] can be used to convert y g of ice at \[0{}^\circ C\] into water at\[100{}^\circ C\], the ratio x:y is:
  A)
  1 : 1  done clear
  B)
  1 : 2  done clear
  C)
  1 : 3  done clear
  D)
  3 : 1 done clear
  View Solution play_arrow

• question_answer9)
  Which of the following will expand the most for same rise in temperature?
  A)
  Aluminium done clear
  B)
  Glass done clear
  C)
  Wood done clear
  D)
  All will expand same done clear
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• question_answer10)
  If \[\alpha ,\,\,\beta \] and \[\gamma \] are coefficient of linear, area and volume expansion respectively, then
  A)
  \[\gamma  = 3\alpha \] done clear
  B)
  \[\alpha = 3\gamma \] done clear
  C)
  \[\beta = 3\alpha \] done clear
  D)
  \[\gamma = 3\beta \] done clear
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• question_answer11)
  An iron tyre is to be fitted on to a wooden wheel 1m in diameter. The diameter of tyre is 6 mm smaller than that of wheel. The tyre should be heated so that its temperature increases by a minimum of (the coefficient of cubical expansion of iron is \[3.6\times {{10}^{-5}})\]
  A)
  \[167{}^\circ C\] done clear
  B)
  \[334{}^\circ C\] done clear
  C)
  \[500{}^\circ C\] done clear
  D)
  \[1000{}^\circ C\] done clear
  View Solution play_arrow

• question_answer12)
  A metal sheet with a circular hole is heated. The hole                                  
  A)
  gets larger              done clear
  B)
  gets smaller done clear
  C)
  remains of the same size done clear
  D)
  gets deformed done clear
  View Solution play_arrow

• question_answer13)
  The coefficient of apparent expansion of mercury in a glass vessel is \[153\times {{10}^{-6}}/{}^\circ C\] and in a steel vessel is \[144\times {{10}^{-6}}/{}^\circ C\]. If a for steel is \[12\times {{10}^{-6}}/{}^\circ C\], then that of glass is
  A)
  \[\] done clear
  B)
  \[6\times {{10}^{-6}}/{}^\circ C\] done clear
  C)
  (c)\[36\times {{10}^{-6}}/{}^\circ C\] done clear
  D)
  \[27\times {{10}^{-6}}/{}^\circ C\] done clear
  View Solution play_arrow

• question_answer14)
  What is the equivalent thermal conductivity of the rods in figure given below, if the length of each cylinder be \[\ell \] and area of cylinder having thermal conductivities\[{{\operatorname{K}}_{1}}\]and \[{{K}_{3}}\]be A while that of the middle cylinder haying thermal conductivity \[{{K}_{2}}\] be 2A?                                                  
  A)
  \[\frac{5}{2\left[ \frac{1}{{{K}_{1}}}+\frac{1}{2{{K}_{2}}}+\frac{1}{{{K}_{3}}} \right]}\] done clear
  B)
  \[\frac{1}{\left[ \frac{1}{{{K}_{1}}}+\frac{1}{2{{K}_{2}}}+\frac{1}{{{K}_{3}}} \right]}\] done clear
  C)
  \[\frac{2}{5\left[ \frac{1}{{{K}_{1}}}+\frac{1}{2{{K}_{2}}}+\frac{1}{{{K}_{3}}} \right]}\]       done clear
  D)
  None of these done clear
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• question_answer15)
  A piece of metal weighs 45g in air and 25g in a liquid of density\[\text{1}\text{.5 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{3}}}\,\text{kg - }{{\text{m}}^{\text{-3}}}\]kept at\[3{{0}^{\operatorname{o}}}C\]. When the temperature of the liquid is raised to\[40{}^\circ C,\], the metal piece weighs 27g. The density of liquid at\[40{}^\circ C\], is\[1.25\times 1{{0}^{3}}kg -{{m}^{-3}}\]. The coefficient of linear expansion of metal is
  A)
  \[1.3\times {{10}^{-3}}/{}^\circ C\] done clear
  B)
  \[5.2\times {{10}^{-3}}/{}^\circ C\] done clear
  C)
  \[2.6\times {{10}^{-3}}/{}^\circ C\] done clear
  D)
  \[0.26\times {{10}^{-3}}/{}^\circ C\] done clear
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• question_answer16)
  On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are \[39{}^\circ  W\] and \[239{}^\circ \] W respectively. What will be the temperature on the new scale, corresponding to a temperature of \[39{}^\circ C\]on the Celsius scale?
  A)
  \[78{}^\circ  W\] done clear
  B)
  \[117{}^\circ W\] done clear
  C)
  \[200{}^\circ W\] done clear
  D)
  \[139{}^\circ W\] done clear
  View Solution play_arrow

• question_answer17)
  A solid ball of metal has a spherical cavity inside it. The ball is heated. The volume of cavity will A
  A)
  decrease         done clear
  B)
         increase done clear
  C)
  remain unchanged done clear
  D)
  have its shape changed done clear
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• question_answer18)
  On a linear temperature scale Y, water freezes at \[160{}^\circ  Y\]and boils at \[- 50{}^\circ  Y\]. On this Y scale, a temperature of 340 K would be read as : (water freezes at 273 K and boils at 373 K)
  A)
  \[-73.7{}^\circ Y\] done clear
  B)
  \[-\,233.7{}^\circ Y\] done clear
  C)
  \[-86.3{}^\circ Y\] done clear
  D)
  \[-106.3{}^\circ Y\] done clear
  View Solution play_arrow

• question_answer19)
  A glass flask is filled up to a mark with 50 cc of mercury at \[18{}^\circ C\]. If the flask and contents are heated to \[38{}^\circ C\], how much mercury will be above the mark? (\[\alpha \] for glass is \[9\times {{10}^{-6}}/{}^\circ C\] and coefficient of real expansion of mercury is \[80\times {{10}^{-6}}/{}^\circ C\])
  A)
  0.85 cc done clear
  B)
  0.46 cc done clear
  C)
  0.153cc done clear
  D)
  0.05 cc done clear
  View Solution play_arrow

• question_answer20)
  A bar of iron is 10 cm at \[20{}^\circ C\]. At \[19{}^\circ C\]it will be (\[\alpha \]of iron\[=11\times {{10}^{-6}}/{}^\circ C\])
  A)
  \[11\times {{10}^{-6}}\] cm longer done clear
  B)
  \[11\times {{10}^{-6}}\]cm shorter done clear
  C)
  \[11\times {{10}^{-5}}\] cm shorter done clear
  D)
  \[11\times {{10}^{-5}}\] cm longer done clear
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• question_answer21)
  Two marks on a glass rod 10 cm apart are found to increase their distance by 0.08 mm when the rod is heated from \[0{}^\circ C\] to \[100{}^\circ C\]. A flask made of the same glass as that of rod measures a volume of 1000 cc at \[0{}^\circ C\]. The volume it measures at \[100{}^\circ C\] in cc is
  A)
  1002.4 done clear
  B)
         1004.2 done clear
  C)
  1006.4 done clear
  D)
         1008.2 done clear
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• question_answer22)
  One end of a uniform rod of length 1 m is placed in boiling water while its other end is placed in melting ice. A point P on the rod is maintained at a constant temperature of \[800{}^\circ C\]. The mass of steam produced per second is equal to the mass of ice melted per second. If specific latent heat of steam is 7 times the specific latent heat of ice, the distance of P from the steam chamber must be
  A)
  (1/7) m done clear
  B)
         (1/8) m  done clear
  C)
  (1/9) m done clear
  D)
         (1/10) m   done clear
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• question_answer23)
  Which of the following circular rods, (given radius r and length /) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?
  A)
  \[\operatorname{r}=2{{r}_{0}};l=2{{l}_{0}}\]     done clear
  B)
  \[\operatorname{r}=2{{r}_{0}};l={{l}_{0}}\] done clear
  C)
  \[\operatorname{r}={{r}_{0}};1=2{{1}_{0}}\]    done clear
  D)
    \[\operatorname{r}={{r}_{0}};1={{1}_{0}}\] done clear
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• question_answer24)
  A beaker contains 200 gm. of water. The heat capacity of the beaker is equal to that of 20 gm. of water. The initial temperature of water in the beaker is \[20{}^\circ C\]. If 440 gm. of hot water at \[92{}^\circ C\]is poured in it, the final temperature, neglecting radiation loss, will be nearest to
  A)
  \[58{}^\circ C\] done clear
  B)
         \[68{}^\circ C\] done clear
  C)
  \[73{}^\circ C\]             done clear
  D)
         \[78{}^\circ C\] done clear
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• question_answer25)
  In a vertical U-tube containing a liquid, the two arms are maintained at different temperatures \[{{t}_{1}}\] and \[{{t}_{2}}\]. The liquid columns in the two arms have heights \[{{l}_{2}}\] respectively. The coefficient of volume expansion of the liquid is equal to  
  A)
  \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{2}}{{t}_{1}}-{{l}_{1}}{{t}_{2}}}\] done clear
  B)
  \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{1}}{{t}_{1}}-{{l}_{1}}{{t}_{1}}}\] done clear
  C)
  \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{2}}{{t}_{1}}-{{l}_{1}}{{t}_{2}}}\] done clear
  D)
  \[\frac{{{l}_{1}}-{{l}_{2}}}{{{l}_{1}}{{t}_{1}}-{{l}_{1}}{{t}_{1}}}\] done clear
  View Solution play_arrow

• question_answer26)
  The coefficient of linear expansion for a certain metal varies with temperature as \[\alpha \](T). If L is the initial length of the metal and the temperature of metal is changed from\[{{\operatorname{T}}_{0}} to T \left( To > T \right)\] , then
  A)
  \[\operatorname{L}={{L}_{0}}\int_{{{T}_{0}}}^{T}{\alpha \left( T \right)dT}\] done clear
  B)
  \[\operatorname{L}={{L}_{0}}\left[ 1+\int_{{{T}_{0}}}^{T}{\alpha \left( T \right)dT} \right]\] done clear
  C)
  \[\operatorname{L}={{L}_{0}}\left[ 1-\int_{{{T}_{0}}}^{T}{\alpha \left( T \right)dT} \right]\] done clear
  D)
  \[\operatorname{L}>{{L}_{0}}\] done clear
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• question_answer27)
  The length of a metallic rod is 5 m at \[0{}^\circ C\]and becomes 5.01 m, on heating up to\[100{}^\circ C\]. The linear expansion of the metal will be
  A)
  \[2.33\times {{10}^{-5}}/{}^\circ C\] done clear
  B)
  \[6.0\times {{10}^{-5}}/{}^\circ C\] done clear
  C)
  \[4.0\times {{10}^{-5}}/{}^\circ C\] done clear
  D)
  \[2.0\times {{10}^{-5}}/{}^\circ C\] done clear
  View Solution play_arrow

• question_answer28)
  A pendulum clock is 5 seconds fast at temperature of \[15{}^\circ C\]and 10 seconds slow at a temperature of\[30{}^\circ C\]. At what temperature does it give the correct time? (take time interval = 24 hours)
  A)
  \[18{}^\circ C\] done clear
  B)
         \[20{}^\circ C\] done clear
  C)
  \[22{}^\circ C\]             done clear
  D)
         \[25{}^\circ C\] done clear
  View Solution play_arrow

• question_answer29)
  A pendulum clock loses 12 s a day if the temperature is \[40{}^\circ C\]and gains 4 s a day if the temperature is\[20{}^\circ C\]. The temperature at which the clock will show correct time, and the co- efficient of linear expansion \[(\alpha )\] of the metal of the pendulum shaft are respectively:
  A)
  \[30{}^\circ C;\,\alpha =1.85\times {{10}^{-3}}/{}^\circ C\]   done clear
  B)
  \[55{}^\circ C;\,\alpha =1.85\times {{10}^{-2}}/{}^\circ C\] done clear
  C)
  \[25{}^\circ C;\,\alpha =1.85\times {{10}^{-5}}/{}^\circ C\] done clear
  D)
  \[60{}^\circ C;\,\alpha =1.85\times {{10}^{-4}}/{}^\circ C\] done clear
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• question_answer30)
  The apparent coefficient of expansion of a liquid when heated in a copper vessel is C and that when heated in a silver vessel is S. If A is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is
  A)
  \[\frac{C+S-3A}{3}\]     done clear
  B)
         \[\frac{C+3A-\operatorname{S}}{3}\] done clear
  C)
  \[\frac{S+3A-C}{3}\]       done clear
  D)
         \[\frac{C+\operatorname{S}-\operatorname{A}}{3}\] done clear
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• question_answer31)
  Coefficient of linear expansion of brass and steel rods are \[{{\alpha }_{1}}\]and \[{{\alpha }_{2}}\]. Lengths of brass and steel rods are \[{{\ell }_{1}}\] and \[{{\ell }_{2}}\] respectively. If \[({{\ell }_{1}}-{{\ell }_{2}})\]is maintained same at all temperatures, which one of the following relations holds good?
  A)
  \[3{{\alpha }_{1}}{{\ell }_{2}}={{\alpha }_{2}}{{\ell }_{1}}\]   done clear
  B)
         \[4{{\alpha }_{1}}{{\ell }_{2}}={{\alpha }_{2}}{{\ell }_{1}}\] done clear
  C)
  \[2{{\alpha }_{1}}{{\ell }_{2}}={{\alpha }_{2}}{{\ell }_{1}}\]    done clear
  D)
         \[{{\alpha }_{1}}{{\ell }_{1}}={{\alpha }_{2}}{{\ell }_{2}}\] done clear
  View Solution play_arrow

• question_answer32)
  It \[{{\operatorname{H}}_{K}}, {{H}_{C}}\]and \[{{H}_{F}}\]are heat required to raise the temperature of one gram of water by one degree in Celsius, Kelvin and Fahrenheit temperature scales respectively then
  A)
  \[{{\operatorname{H}}_{K}}>{{H}_{C}}>{{H}_{F}}\] done clear
  B)
  \[{{\operatorname{H}}_{F}}>{{H}_{C}}>{{H}_{K}}\] done clear
  C)
  \[{{\operatorname{H}}_{K}}={{H}_{C}}>{{H}_{F}}\] done clear
  D)
  \[{{\operatorname{H}}_{K}}={{H}_{C}}>{{H}_{F}}\] done clear
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• question_answer33)
  A mass of 50g of water in a closed vessel, with surroundings at a constant temperature takes 2 minutes to cool from \[30{}^\circ C\] to\[25{}^\circ C\]. A mass of 100g of another liquid in an identical vessel with identical surroundings takes the same time to cool from \[30{}^\circ C\] to \[25{}^\circ C\]. The specific heat of the liquid is: (The water equivalent of the vessel is 30g.)   
  A)
  2.0 kcal/kg done clear
  B)
  7 kcal/kg done clear
  C)
  3 kcal/kg done clear
  D)
  0.5 kcal/kg done clear
  View Solution play_arrow

• question_answer34)
  The coefficient of linear expansion of glass is \[{{\alpha }_{g}}\] per \[{}^\circ C\]and the cubical expansion of mercury is y\[{{\gamma }_{m}}\] per \[{}^\circ C\]. The volume of the bulb of a mercury thermometer at \[0{}^\circ C\]is \[{{V}_{0}}\] and cross section of the capillary is \[{{\operatorname{A}}_{0}}\]. What is the length of mercury column in capillary at \[T{}^\circ C\], if the mercury just fills the bulb at \[0{}^\circ C\]?
  A)
  \[\frac{{{\operatorname{V}}_{0}}T\left( {{\gamma }_{\operatorname{m}}}+3{{\alpha }_{\operatorname{g}}} \right)}{{{\operatorname{A}}_{0}}\left( 1+2{{\alpha }_{\operatorname{g}}}T \right)}\] done clear
  B)
   \[\frac{{{\operatorname{V}}_{0}}T\left( {{\gamma }_{\operatorname{m}}}-3{{\alpha }_{\operatorname{g}}} \right)}{{{\operatorname{A}}_{0}}\left( 1+2{{\alpha }_{\operatorname{g}}}T \right)}\] done clear
  C)
  \[\frac{{{\operatorname{V}}_{0}}T\left( {{\gamma }_{\operatorname{m}}}+2{{\alpha }_{\operatorname{g}}} \right)}{{{\operatorname{A}}_{0}}\left( 1+3{{\alpha }_{\operatorname{g}}}T \right)}\] done clear
  D)
  \[\frac{{{\operatorname{V}}_{0}}T\left( {{\gamma }_{\operatorname{m}}}-2{{\alpha }_{\operatorname{g}}} \right)}{{{\operatorname{A}}_{0}}\left( 1+3{{\alpha }_{\operatorname{g}}}T \right)}\] done clear
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• question_answer35)
  The density of water at \[4{}^\circ C\]is\[1000.0 kg/{{m}^{3}}\]and at \[100{}^\circ C\] it is \[958.4 kg/{{m}^{3}}\]. The cubic expansively of water between these temperatures is
  A)
  \[4.5\times {{10}^{-3}}/K\] done clear
  B)
  \[5.4\times {{10}^{-5}}/K\] done clear
  C)
  \[4.5\times {{10}^{-4}}/K\] done clear
  D)
  \[5.4\times {{10}^{-6}}/K\] done clear
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• question_answer36)
  A rod PQ of length is pivoted tan end P and freely rotated in a horizontal plane at an angular speed \[\omega \] about a vertical axis passing through P. If coefficient of line are x pansion of material of rod is \[\alpha \], find the percentage change in it sangular velocity if temperature of system is increased by \[\Delta \,T\] is
  A)
  \[(\alpha \,\Delta T\times 100)%\]% done clear
  B)
  \[(2\alpha \,\Delta T\times 100)%\]% done clear
  C)
  \[(3\alpha \,\Delta T\times 100)\times 100%\]% done clear
  D)
  \[(4\alpha \,\Delta T\times 100)%\]% done clear
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• question_answer37)
  A steel rod of length 1 m is heated from \[25{}^\circ C\] to \[75{}^\circ C\] keeping its length constant. The longitudinal strain developed in the rod is (Given: Coefficient of linear expansion of steel \[=12\times {{10}^{-6}}/{}^\circ C\])
  A)
  \[6\times {{10}^{-6}}\] done clear
  B)
  \[-6\times {{10}^{-5}}\] done clear
  C)
  \[-6\times {{10}^{-4}}\] done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer38)
  A steel rail of length 5 m and area of cross-section \[40 c{{m}^{2}}\]is prevented from expanding along its length while the temperature rises by \[10{}^\circ C\]. If coefficient of linear expansion and Young's modulus of steel are \[1.2\times l{{0}^{-5}} {{K}^{-1}}\] and \[2\times 1{{0}^{11}}\]\[{{\operatorname{Nm}}^{-2}}\] respectively, the force developed in the rail is approximately:                  
  A)
  \[2\times 1{{0}^{7}}N\] done clear
  B)
  \[1\times 1{{0}^{5}}N\] done clear
  C)
  \[2\times 1{{0}^{9}}N\]            done clear
  D)
  \[3\times 1{{0}^{-5}}N\] done clear
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• question_answer39)
  When a block of iron floats in mercury at \[0{}^\circ C\], fraction \[{{k}_{1}}\] of its volume is submerged, while at the temperature \[60 {}^\circ C\], a fraction \[{{k}_{2}}\] is seen to be submerged. If the coefficient of volume expansion of iron is \[{{\gamma }_{Fe}}\] and that of mercury is \[{{\gamma }_{Hg}}\] then the ratio \[{{\operatorname{k}}_{1}}/{{k}_{2}}\]can be expressed as
  A)
  \[\frac{1+60{{\gamma }_{Fe}}}{1+60{{\gamma }_{hg}}}\] done clear
  B)
  \[\frac{1-60{{\gamma }_{Fe}}}{1+60{{\gamma }_{Hg}}}\] done clear
  C)
  \[\frac{1+60{{\gamma }_{Fe}}}{1-60{{\gamma }_{Hg}}}\] done clear
  D)
  \[\frac{1+60{{\gamma }_{Fe}}}{1+60{{\gamma }_{Hg}}}\] done clear
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• question_answer40)
  The density of steel at \[0 {}^\circ C\]is 8.0 g/cc. At what temperature is density lesser by 0.1%? Coefficient of linear expansion of steel is \[1{{0}^{-5}} /{}^\circ C\].
  A)
  \[37.2{}^\circ C\] done clear
  B)
  \[33.3{}^\circ C\] done clear
  C)
  \[55.4{}^\circ C\] done clear
  D)
  \[40.2{}^\circ C\] done clear
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• question_answer41)
  A thin steel ring of inner diameter 40 cm and cross- sectional area \[1 m{{m}^{2}}\], is heated until it easily slides on a rigid cylinder of diameter 40.05 cm. [For steel,\[\alpha =1{{0}^{-5}}/{}^\circ C, Y= 200 GPa\]] When the ring cools down, the tension in the ring will be:               
  A)
  1000 N done clear
  B)
  500 N done clear
  C)
  250 N done clear
  D)
  100 N done clear
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• question_answer42)
  Consider two identical iron spheres, one which lie on a thermally insulating plate, while the other hangs from an insulating thread. Equal amount of heat is supplied to the two spheres  
  A)
  temperature of A will be greater than B done clear
  B)
  temperature of B will be greater than A done clear
  C)
  their temperature will be equal done clear
  D)
  can't be predicted done clear
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• question_answer43)
  A horizontal tube, open at both ends, contains a column of liquid. The length of this liquid column does not change with temperature. Let \[\gamma \]= coefficient of volume expansion of the liquid and \[\alpha \]= coefficient of linear expansion of the material of the tube, then
  A)
  \[\gamma =\alpha \] done clear
  B)
  \[\gamma =2\alpha \] done clear
  C)
  \[\gamma =3\alpha \] done clear
  D)
  \[\gamma =0\] done clear
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• question_answer44)
  A cylindrical steel alloy is inserted into a circular hole of diameter 2.60 m in a brass plate. When the plug and the plate are at a temperature \[20{}^\circ C\], the diameter of the plug is 0.010 mm smaller than that of the hole. The temperature at which the plug will just fit in is (given and \[{{\alpha }_{steel}}=11\times \]\[1{{0}^{-6}}/{}^\circ C\]and\[{{\alpha }_{brass}} =19\times 1{{0}^{-6}}/{}^\circ C\])
  A)
  \[-\,20{}^\circ  C\] done clear
  B)
  \[-\,48{}^\circ  C\] done clear
  C)
  \[10{}^\circ  C\] done clear
  D)
  None of these done clear
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• question_answer45)
  The ratio of the coefficient of volume expansion of a glass container to that of a viscous liquid kept inside the container is 1 : 4. What fraction of the inner volume of the container should the liquid occupy so that the volume of the remaining vacant space will be same.at all temperatures?
  A)
  2 : 5 done clear
  B)
  1 : 4 done clear
  C)
  1 : 64 done clear
  D)
  1 : 8 done clear
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• question_answer46)
  An iron tyre is to be fitted on to a wooden wheel 1m in diameter. The diameter of tyre is 6 mm smaller than that of wheel. The tyre should be heated so that its temperature increases by a minimum of (the coefficient of cubical expansion of iron is\[3.6\times {{10}^{-5}}/{}^\circ C\])             
  A)
  \[167{}^\circ C\] done clear
  B)
  \[334{}^\circ C\] done clear
  C)
  \[500{}^\circ C\] done clear
  D)
  \[1000{}^\circ C\] done clear
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• question_answer47)
  Mass of water which absorbs or emits the same amount of heat as is done by the body for the same rise or fall in temperature is known as
  A)
  thermal capacity of the body done clear
  B)
  specific heat capacity of the body done clear
  C)
  latent heat capacity of the body done clear
  D)
  water equivalent of the body done clear
  View Solution play_arrow

• question_answer48)
  A lead bullet strikes against a steel plate with a velocity \[200 m {{s}^{-1}}\]. If the impact is perfectly inelastic and the heat produced is equally shared between the bullet and the target, then the rise in temperature of the bullet is (specific heat capacity of lead \[=125J\,k{{g}^{-l}}{{K}^{-l}}\])
  A)
  \[80{}^\circ C\] done clear
  B)
  \[60{}^\circ C\] done clear
  C)
  \[160{}^\circ C\] done clear
  D)
  \[40{}^\circ C\] done clear
  View Solution play_arrow

• question_answer49)
  Certain amount of heat is given to 100 g of copper to increase its temperature by \[21{}^\circ C\]. If the same amount of heat is given to 50 g of water, then the rise in its temperature is (Specific heat capacity of copper\[=400J k{{g}^{-1}} {{K}^{-1}}\] and that for water =\[4200 J k{{g}^{-1}} {{K}^{-1}}\])
  A)
  \[4{}^\circ C\] done clear
  B)
  \[5.25{}^\circ C\] done clear
  C)
  \[8{}^\circ C\] done clear
  D)
  \[6{}^\circ C\] done clear
  View Solution play_arrow

• question_answer50)
  A hammer of mass 1 kg having speed of 50 m/s, hit a iron nail of mass 200 gm. If specific heat of iron is \[0.105 cal/gm\,{}^\circ C\]and half the energy is converted into heat. the raise in temperature of nail is
  A)
  \[7.1{}^\circ C\] done clear
  B)
  \[9.2{}^\circ C\] done clear
  C)
  \[10.5{}^\circ C\] done clear
  D)
  \[12.1{}^\circ C\] done clear
  View Solution play_arrow

• question_answer51)
  In an energy recycling process, \[100\text{ }g\] of steam at \[100{}^\circ C\]becomes water at \[100{}^\circ C\] which converts y g of ice at \[0{}^\circ C\] into water at \[100{}^\circ C\]. The numeric value of y is
  A)
  100  done clear
  B)
  200   done clear
  C)
  300 done clear
  D)
  400 done clear
  View Solution play_arrow

• question_answer52)
  In a water-fall the water falls from a height of 100 m. If the entire K.E. of water is converted into heat, the rise in temperature of water will be
  A)
  \[0.23{}^\circ C\] done clear
  B)
  \[0.46{}^\circ C\] done clear
  C)
  \[2.3{}^\circ C\] done clear
  D)
  \[0.023{}^\circ C\] done clear
  View Solution play_arrow

• question_answer53)
  A student takes 50gm wax (specific heat = 0.6\[\operatorname{kcal}/kg{}^\circ C\]) and heats it till it boils. The graph between temperature and time is as follows. Heat supplied to the wax per minute and boiling point are respectively          
  A)
  \[500cal, 50{}^\circ C\] done clear
  B)
  \[1000cal, 100{}^\circ C\] done clear
  C)
  \[1500cal, 200{}^\circ C\] done clear
  D)
  \[1000cal, 200{}^\circ C\] done clear
  View Solution play_arrow

• question_answer54)
  19 g of water at \[30{}^\circ C\] and 5 g of ice at \[-\,20{}^\circ C\]are mixed together in a calorimeter. What is the final temperature of the mixture? Given specific heat of ice \[=0.5 cal {{g}^{-1}} {{\left( {}^\circ C \right)}^{-1}}\]and latent heat of fusion of ice\[=80cal\,\,{{g}^{-1}}\]
  A)
  \[0{}^\circ C\] done clear
  B)
  \[-5{}^\circ C\] done clear
  C)
  \[5{}^\circ C\] done clear
  D)
  \[10{}^\circ C\] done clear
  View Solution play_arrow

• question_answer55)
  The heat \[(Q)\] supplied to a solid, which is otherwise thermally isolated from its surroundings, is plotted as a function of its absolute temperature, \[\theta \]. It is found that they are related by the equation. \[Q=a\,{{\theta }^{2}}+b\,{{\theta }^{4}}\](a, b are constants). The heat capacity of the solid is given by
  A)
  \[a\frac{{{\theta }^{3}}}{3}+b\frac{{{\theta }^{5}}}{5}\] done clear
  B)
  \[a\theta +b{{\theta }^{3}}\] done clear
  C)
  \[a\frac{\theta }{3}+b\frac{{{\theta }^{3}}}{5}\] done clear
  D)
  \[2a\theta +4b{{\theta }^{3}}\] done clear
  View Solution play_arrow

• question_answer56)
  A 2 kg copper block is heated to \[500{}^\circ C\]and then it is placed on a large block of ice at \[0{}^\circ C\]. If the specific heat capacity of copper is \[400 J/kg{}^\circ C\]and latent heat of fusion of water is \[3.5\times l{{0}^{5}} J/\] kg, the amount of ice that can melt is
  A)
  (7/8) kg done clear
  B)
         (7/5) kg done clear
  C)
  (8/7) kg done clear
  D)
         (5/7) kg done clear
  View Solution play_arrow

• question_answer57)
  Two spheres of different materials one with triple the radius and one-fifth wall thickness of the other are filled with ice. If the time taken for complete melting of ice in the larger sphere is 30 minute and for smaller one is 20 minute, the ratio of thermal conductivities of the materials of larger spheres to that of smaller sphere is   
  A)
  1/8 done clear
  B)
  3/4    done clear
  C)
  2/3 done clear
  D)
  1/2 done clear
  View Solution play_arrow

• question_answer58)
  Five rods of same dimensions are arranged as shown in the figure. They have thermal conductivities\[50{}^\circ C\]and \[{{K}_{5}}\]. When points A and B are maintained at different temperatures, no heat flows through the central rod if
  A)
  \[{{\operatorname{K}}_{1}}= {{K}_{4}}and {{K}_{2}}={{\operatorname{K}}_{3}}\] done clear
  B)
  \[{{\operatorname{K}}_{1}}{{K}_{4}}\,and {{K}_{2}}\,{{\operatorname{K}}_{3}}\] done clear
  C)
  \[{{\operatorname{K}}_{1}}{{K}_{2}}\,={{K}_{3}}\,{{\operatorname{K}}_{4}}\] done clear
  D)
  \[\frac{{{K}_{1}}}{{{K}_{4}}}=\frac{{{K}_{2}}}{{{K}_{3}}}\] done clear
  View Solution play_arrow

• question_answer59)
  Ice starts forming in a lake with water at \[0{}^\circ C\]when the atmospheric temperature is \[-10{}^\circ C\]. If the time taken for the first 1 cm of ice to be formed is 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is
  A)
  7 hours          done clear
  B)
         14 hours done clear
  C)
  21 hours     done clear
  D)
         3.5 hours done clear
  View Solution play_arrow

• question_answer60)
  A kettle with 3 liter water at \[27{}^\circ C\] is heated by operating coil heater of power 2 kW. The heat is lost to the atmosphere at constant rate 130 J/sec, when its lid is open. In how much time will water heated to \[97{}^\circ C\] with the lid open? (specific heat of water =4.2kJ/kg)
  A)
  472 sec              done clear
  B)
  693 sec done clear
  C)
  912 sec              done clear
  D)
  1101 sec done clear
  View Solution play_arrow

• question_answer61)
  The two ends of a metal rod are maintained at temperatures \[100{}^\circ C\] and \[110{}^\circ C\]. The rate of heat flow in the rod is found to be 4.0 J/s. If the ends are maintained at temperatures \[200{}^\circ C\] and \[210{}^\circ C\], the rate of heat flow will be
  A)
  16.8 J/s done clear
  B)
  8.0 J/s done clear
  C)
  4.0 J/s done clear
  D)
  44.0 J/s done clear
  View Solution play_arrow

• question_answer62)
  One end of a thermally insulated rod is kept at a temperature \[{{T}_{1}}\] and the other at \[{{l}_{2}}\]. The rod is composed of two sections of length \[{{l}_{2}}\] and\[{{l}_{1}}\] thermal conductivities \[{{\operatorname{K}}_{1}}\] and \[{{K}_{2}}\]respectively. The temperature at the interface of the two section is  
  A)
  \[\frac{\left( {{K}_{1}}{{l}_{1}}{{T}_{1}}+{{K}_{2}}{{l}_{2}}{{T}_{2}} \right)}{\left( {{K}_{1}}{{l}_{1}}+{{K}_{2}}{{l}_{2}} \right)}\] done clear
  B)
  \[\frac{\left( {{K}_{2}}{{l}_{2}}{{T}_{1}}+{{K}_{1}}{{l}_{1}}{{T}_{2}} \right)}{\left( {{K}_{1}}{{l}_{1}}+{{K}_{2}}{{l}_{2}} \right)}\] done clear
  C)
  \[\frac{\left( {{K}_{2}}{{l}_{1}}{{T}_{1}}+{{K}_{1}}{{l}_{2}}{{T}_{2}} \right)}{\left( {{K}_{1}}{{l}_{1}}+{{K}_{2}}{{l}_{2}} \right)}\] done clear
  D)
  \[\frac{\left( {{K}_{1}}{{l}_{2}}{{T}_{1}}+{{K}_{2}}{{l}_{1}}{{T}_{2}} \right)}{\left( {{K}_{1}}{{l}_{1}}+{{K}_{2}}{{l}_{2}} \right)}\] done clear
  View Solution play_arrow

• question_answer63)
  A black body is at a temperature of 2880 K. The energy of radiation emitted by this object with wavelength between 499 nm and 500 nm is \[{{U}_{1}}\] between 999 nm and 1000 nm is \[{{\operatorname{U}}_{2}}\] and between 1499 nm and 1500 nm is \[{{\operatorname{U}}_{3}}\] Wien's constant \[\operatorname{b}=2.88\times {{10}^{6}}nm-K\]. Then
  A)
  \[{{\operatorname{U}}_{1}}=0\] done clear
  B)
  \[{{\operatorname{U}}_{2}}=0\] done clear
  C)
  \[{{\operatorname{U}}_{1}}={{U}_{2}}\] done clear
  D)
  \[{{\operatorname{U}}_{2}}>{{U}_{1}}\] done clear
  View Solution play_arrow

• question_answer64)
  A cylindrical rod of aluminum is of length 20 cm, and radius 2 cm. The two ends are maintained at temperatures of \[0{}^\circ C\] and \[50{}^\circ C\] [the coefficient of thermal conductivity is \[\frac{0.5\,cal}{cm\times sec{{\times }^{o}}C}\] ]Then the thermal resistance of the rod in \[\frac{cal}{sec{{\times }^{o}}C}\]
  A)
  318       done clear
  B)
         31.8   done clear
  C)
  3.18      done clear
  D)
         0.318 done clear
  View Solution play_arrow

• question_answer65)
  A metal ball of surface area 200 square cm, temperature \[527{}^\circ C\] is surrounded by a vessel at\[27{}^\circ C\]. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is approximately \[\left[ \sigma = 5.67\times 1{{0}^{-8}}\frac{Joule}{{{m}^{2}}\times sec\times {{K}^{2}}} \right]\]         
  A)
  108 joule done clear
  B)
  168 joule done clear
  C)
  182 joule done clear
  D)
  192 joule done clear
  View Solution play_arrow

• question_answer66)

  Two rods of same length and transfer a given amount of heat 12 second, when they are joined as shown in figure

  (i) But when they are joined as shown in figure

  (ii) then they will transfer same heat in same conditions in

  
  A)
  24 s done clear
  B)
  13 s       done clear
  C)
  15 s done clear
  D)
  48 s done clear
  View Solution play_arrow

• question_answer67)
  The rectangular surface of area \[8 cm\times 4 cm\]of a black body at temperature \[127{}^\circ C\] emits energy E per second. If the length and breadth are reduced to half of the initial value and the temperature is raised to \[327{}^\circ C\], the rate of emission of energy becomes
  A)
  \[\frac{3}{8}\operatorname{E}\] done clear
  B)
  \[\frac{81}{16}\operatorname{E}\] done clear
  C)
  \[\frac{9}{16}\operatorname{E}\] done clear
  D)
  \[\frac{81}{64}\operatorname{E}\] done clear
  View Solution play_arrow

• question_answer68)
  A tube shaped like a parallelogram is filled with liquid is kept in a vertical plane. Tube is heated at mid-point of ad. The heat flows only by convection. Then   
  A)
  \[{{\operatorname{T}}_{d}}={{T}_{a}}>{{T}_{b}}={{T}_{c}}\] done clear
  B)
  \[{{\operatorname{T}}_{a}}>{{T}_{b}}>{{T}_{c}}>{{T}_{d}}\] done clear
  C)
  \[{{\operatorname{T}}_{a}}>{{T}_{b}}>{{T}_{d}}={{T}_{c}}\] done clear
  D)
  \[{{\operatorname{T}}_{d}}>{{T}_{a}}>{{T}_{b}}>{{T}_{c}}\] done clear
  View Solution play_arrow

• question_answer69)
  In the plot of temperature versus time showing changes in the state of ice on heating, which part represents constant temperature?
  A)
  OA done clear
  B)
  AB done clear
  C)
  CD done clear
  D)
  All of these done clear
  View Solution play_arrow

• question_answer70)
  A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is: [Latent heat of ice is \[3.4\times 1{{0}^{5}}\]J/kg and g=10N/kg]
  A)
  34 km done clear
  B)
  544 km done clear
  C)
  136 km done clear
  D)
  68 km done clear
  View Solution play_arrow

• question_answer71)
  12 identical rods made of same material are arranged in the form of a cube. The temperature of P and R are maintained at \[90{}^\circ C\] and \[30{}^\circ C\]respectively. Then the temperature of point V, when steady state is reached is
  A)
  \[65{}^\circ C\] done clear
  B)
  \[60{}^\circ C\] done clear
  C)
  \[20{}^\circ C\] done clear
  D)
  \[50{}^\circ C\] done clear
  View Solution play_arrow

• question_answer72)
  A sphere and a cube of same material and same volume are heated upto same temperature and allowed to cool in the same surroundings. The ratio of the amounts of radiations emitted will be
  A)
  1 : 1                  done clear
  B)
         \[\frac{4\pi }{3}:1\] done clear
  C)
  \[{{\left( \frac{\pi }{6} \right)}^{1/3}}:1\]           done clear
  D)
         \[\frac{1}{2}{{\left( \frac{4\pi }{3} \right)}^{2/3}}:1\] done clear
  View Solution play_arrow

• question_answer73)
  Four identical rods of same material are joined end to end to form a square. If the temperature difference between the ends of a diagonal is\[100{}^\circ C\], then the temperature difference between the ends of other diagonal will be (where / is the length of each rod)
  A)
  \[0{}^\circ C\] done clear
  B)
  \[\frac{100}{l}{}^\circ C\] done clear
  C)
  \[\frac{100}{2l}{}^\circ C\] done clear
  D)
  \[100{}^\circ C\] done clear
  View Solution play_arrow

• question_answer74)
  The figure shows a system of two concentric spheres of radii \[{{\operatorname{r}}_{1}}\]and \[{{r}_{2}}\] are kept at temperatures \[{{T}_{1}}\] and \[{{T}_{2}}\]respectively. The radial rate of flow of heat in a substance between the two concentric spheres is proportional to
  A)
  \[ln\left( \frac{{{r}_{2}}}{{{r}_{1}}} \right)\] done clear
  B)
  \[\frac{\left( {{r}_{2}}-{{r}_{1}} \right)}{\left( {{r}_{1}}{{r}_{2}} \right)}\] done clear
  C)
  \[\left( {{r}_{2}}-{{r}_{1}} \right)\] done clear
  D)
  \[\frac{{{r}_{1}}\,{{r}_{2}}}{({{r}_{2}}-{{r}_{1}})}\]   done clear
  View Solution play_arrow

• question_answer75)
  300 gm of water at \[25{}^\circ C\]is added to 100 g of ice at\[0{}^\circ C\]. The final temperature of the mixture is
  A)
  \[-\frac{5}{3}{}^\circ \text{C}\] done clear
  B)
  \[-\frac{5}{2}{}^\circ C\] done clear
  C)
  \[5{}^\circ C\]   done clear
  D)
  \[0{}^\circ C\] done clear
  View Solution play_arrow

• question_answer76)
  A slab of stone of area \[0.36 {{m}^{2}}\]and thickness 0.1 m is exposed on the lower surface to steam at\[100{}^\circ C\]. A block of ice at \[0{}^\circ C\] rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is: (Given latent heat effusion of ice \[=3.36\times 105 J\]\[{{\operatorname{kg}}^{-1}}\].):  
  A)
  \[1.24J/m{}^\circ C\]                 done clear
  B)
  \[1.29J/m{}^\circ C\] done clear
  C)
  \[2.05J/m{}^\circ C\]     done clear
  D)
         \[1.02J/m{}^\circ C\] done clear
  View Solution play_arrow

• question_answer77)
  A partition wall has two layers of different materials A and B in contact with each other. They have the same thickness but the thermal conductivity of layer A is twice that of layer B. At steady state the temperature difference across the layer B is 50 K, then the corresponding difference across the layer A is
  A)
  50 K done clear
  B)
  12.5 K done clear
  C)
  25 K done clear
  D)
  60 K done clear
  View Solution play_arrow

• question_answer78)
  The tempertaure of equal masses of three different liquids A, B and C are \[12{}^\circ C, 19{}^\circ C\] and \[28{}^\circ C\] respectively. The temperature when A and B are mixed is \[16{}^\circ C\] and when B and C are mixed is \[23{}^\circ C\]. The temperature when A and C are mixed is
  A)
  \[18.2{}^\circ C\] done clear
  B)
  \[22{}^\circ C\] done clear
  C)
  \[20.2{}^\circ C\] done clear
  D)
  \[25.2{}^\circ C\] done clear
  View Solution play_arrow

• question_answer79)
  2 kg of ice at \[-20{}^\circ C\] is mixed with 5kg of water at \[20{}^\circ C\] in an insulating vessel having a negligible heat capacity. Calculate the final mass of water remaining in the container. It is given that the specific heats of water & ice are\[1k cal/kg/{}^\circ C\] & \[0.5 kcal/kg/{}^\circ C\]while the latent heat effusion of ice is 80 kcal/kg
  A)
  7 kg done clear
  B)
  6 kg  done clear
  C)
  4 kg done clear
  D)
  2 kg done clear
  View Solution play_arrow

• question_answer80)
  An experiment takes 10 minutes to raise the temperature of water in a container from \[0{}^\circ C\]to \[100{}^\circ C\]and another 55 minutes to convert it totally into steam by a heater supplying heat at a uniform rate. Neglecting the specific heat of the container and taking specific heat of water to be\[1 cal/g{}^\circ C\], the heat of vapourisation according to this experiment will come out to be :
  A)
  560 cal/g done clear
  B)
  550 cal/g done clear
  C)
  540 cal/g done clear
  D)
  530 cal/g done clear
  View Solution play_arrow

• question_answer81)
  The room heater can maintain only \[16{}^\circ C\] in the room when the temperature outside is \[-20{}^\circ C\]. It is not warm and comfortable, that is why the electric stove with power of 1 kW is also plugged in. Together these two devices maintain the room temperature of \[22{}^\circ C\]. Determine the thermal power of the heater.             
  A)
  3 kW done clear
  B)
  4 kW done clear
  C)
  5 kW done clear
  D)
  6 kW done clear
  View Solution play_arrow

• question_answer82)
  Three liquids of equal volumes are thoroughly mixed. If their specific heats are \[{{\operatorname{s}}_{1}},\,\,{{s}_{2}},\,\,{{s}_{3}}\] and their temperatures \[{{\theta }_{1}},{{\theta }_{2}},{{\theta }_{3}}\] and their masses \[{{\operatorname{m}}_{1}},\,\,{{m}_{2}},\,\,{{m}_{3}}\] respectively, then the final temperature of the mixture is
  A)
  \[\frac{{{s}_{1}}{{\theta }_{1}}+{{s}_{2}}{{\theta }_{2}}+{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{s}_{1}},\,\,{{m}_{2}}{{s}_{2}},\,\,{{m}_{3}}{{s}_{3}}}\] done clear
  B)
  \[\frac{{{m}_{1}}{{s}_{1}}{{\theta }_{1}}+{{m}_{2}}{{s}_{2}}{{\theta }_{2}}+{{m}_{3}}{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{s}_{1}},\,\,{{m}_{2}}{{s}_{2}},\,\,{{m}_{3}}{{s}_{3}}}\] done clear
  C)
  \[\frac{{{m}_{1}}{{s}_{1}}{{\theta }_{1}}+{{m}_{2}}{{s}_{2}}{{\theta }_{2}}+{{m}_{3}}{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{\theta }_{1}},\,\,{{m}_{2}}{{\theta }_{2}},\,\,{{m}_{3}}{{\theta }_{3}}}\] done clear
  D)
  \[\frac{{{m}_{1}}{{\theta }_{1}}+{{m}_{2}}{{\theta }_{2}}+{{m}_{3}}{{\theta }_{3}}}{{{\operatorname{s}}_{1}}{{\theta }_{1}},\,\,{{\operatorname{s}}_{2}}{{\theta }_{2}},\,\,{{\operatorname{s}}_{3}}{{\theta }_{3}}}\] done clear
  View Solution play_arrow

• question_answer83)
  A body cools from \[50.0{}^\circ C\] to \[49.9{}^\circ C\] in 5s. How long will it take to cool from \[40.0{}^\circ C\]to\[39.9{}^\circ C\]? Assume the temperature of surroundings to be \[30.0{}^\circ C\] and Newton's law of cooling to be valid
  A)
  2.5 s                             done clear
  B)
  10 s done clear
  C)
  20 s                  done clear
  D)
         5 s done clear
  View Solution play_arrow

• question_answer84)
  A container contains hot water at \[100{}^\circ C\]. If in time \[{{T}_{1}}\] temperature falls to \[80{}^\circ C\] and the time \[{{T}_{2}}\] temperature falls to \[60{}^\circ C\] form \[80{}^\circ C\], then
  A)
  \[{{T}_{1}}={{T}_{2}}\]          done clear
  B)
         \[{{T}_{1}}>{{T}_{2}}\] done clear
  C)
  \[{{T}_{1}}<{{T}_{2}}\]          done clear
  D)
         None of these done clear
  View Solution play_arrow

• question_answer85)
  According to Newton's law of cooling, the rate of cooling of a body is proportional to \[{{\left( \Delta \theta  \right)}^{n}}\], where \[\Delta \theta \] is the difference of the temperature of the body and the surroundings, and n is equal to
  A)
  two       done clear
  B)
         three done clear
  C)
  four                   done clear
  D)
  one done clear
  View Solution play_arrow

• question_answer86)
  A body cools in a surrounding which is at a constant temperature of \[{{\theta }_{0}}\]. Assume that it obeys Newton's law of cooling. Its temperature\[\theta \]is plotted against time t. Tangents are drawn to the curve at the points\[P\left( \theta ={{\theta }_{2}} \right)\]and\[Q\left( \theta ={{\theta }_{1}} \right)\]. These tangents meet the time axis at angle of\[{{\phi }_{2}}\] and \[{{\phi }_{1}}\], as shown, then 
  A)
  \[\frac{\tan {{\phi }_{2}}}{\tan {{\phi }_{1}}}=\frac{{{\theta }_{1}}-{{\theta }_{0}}}{{{\theta }_{2}}-{{\theta }_{0}}}\] done clear
  B)
  \[\frac{\tan {{\phi }_{2}}}{\tan {{\phi }_{1}}}=\frac{{{\theta }_{2}}-{{\theta }_{0}}}{{{\theta }_{1}}-{{\theta }_{0}}}\] done clear
  C)
   \[\frac{\tan {{\phi }_{1}}}{\tan {{\phi }_{2}}}=\frac{{{\theta }_{1}}}{{{\theta }_{2}}}\] done clear
  D)
   \[\frac{\tan {{\phi }_{1}}}{\tan {{\phi }_{2}}}=\frac{{{\theta }_{2}}}{{{\theta }_{1}}}\] done clear
  View Solution play_arrow

• question_answer87)
  Consider two hot bodies \[{{\operatorname{B}}_{1}}\] and \[{{B}_{2}}\]which have temperatures \[109{}^\circ C\] and  \[89{}^\circ C\]respectively at t=0. The temperature of the surroundings is\[49{}^\circ C\]. The ratio of the respective rates of cooling \[{{R}_{1}}\] and \[{{R}_{2}}\]of these two bodies at t = 0 will be
  A)
  \[{{R}_{1}}:{{R}_{2}}=3:2\]     done clear
  B)
  \[{{R}_{1}}:{{R}_{2}}=5:4\] done clear
  C)
  \[{{R}_{1}}:{{R}_{2}}=2:3\]     done clear
  D)
         \[{{R}_{1}}:{{R}_{2}}=4:5\] done clear
  View Solution play_arrow

• question_answer88)
  A cube, a pyramid (with faces identical) and a sphere (all of them hollow) are made from the < same material and have equal mass and bound equal volume. They are heated to the same temperature and then left to cool. After some time,

  1. sphere will have the highest temperature

  2. pyramid will have the highest temperature.

  3. cube will have the lowest temperature.

  4. sphere will have the lowest temperature.

  5. pyramid will have the lowest temperature Correct option will be:

  A)
                      2 and 3             done clear
  B)
         3 and 1 done clear
  C)
  1 and 5             done clear
  D)
         2 and 4 done clear
  View Solution play_arrow

• question_answer89)
  A sphere of density p, specific heat capacity c and radius r is hung by a thermally insulating thread in an enclosure which is kept at a lower temperature than the sphere. The temperature of the sphere starts to drop at a rate which depends upon the temperature difference between the sphere and the enclosure and the nature of the surface of sphere and is proportional to
  A)
  \[\frac{c}{{{r}^{3}}\rho }\] done clear
  B)
  \[\frac{1}{{{r}^{3}}\rho c}\] done clear
  C)
  \[3{{r}^{3}}\rho c\] done clear
  D)
  \[\frac{1}{r\rho c}\] done clear
  View Solution play_arrow

• question_answer90)
  A hot body, obeying Newton's law of cooling is cooling down from its peak value \[89{}^\circ C\] to an ambient temperature of \[39{}^\circ C\]. It takes 5 minutes in cooling down from \[89{}^\circ C\] to \[49{}^\circ C\]. How much time will it take to cool down from \[62{}^\circ C to 32{}^\circ C\](Given In 2 = 9.693, In 5 = 1.699)
  A)
  3.75 minutes done clear
  B)
  8.6 minutes done clear
  C)
  9.6 minutes done clear
  D)
  6.5 minutes done clear
  View Solution play_arrow

• question_answer91)
  Which of the given graphs proves Newton's law of cooling? 
  A)
  done clear
  B)
  done clear
  C)
  done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer92)
  A body cools in a surrounding of constant temperature \[39{}^\circ C\]. Its heat capacity is\[2J/kg {}^\circ C\]. Initial temperature of the body is\[49{}^\circ C\]. Assume Newton's law of cooling is valid. The body cools to \[38{}^\circ C\] in 19 minutes. In further 19 minutes it will cool from \[38{}^\circ C\] to
  A)
  \[36{}^\circ C\]             done clear
  B)
         \[36.4{}^\circ C\] done clear
  C)
  \[37{}^\circ C\]             done clear
  D)
         \[37.5{}^\circ C\] done clear
  View Solution play_arrow

• question_answer93)
  A 5.9 g bullet (specific heat of material of bullet =\[128 J/kg{}^\circ C\]) moving with a velocity of 299 m/s enters a sand bag and stops. If the entire kinetic energy of the bullet is changed into heat energy that is added to the bullet, then the rise in the temperature of the bullet is   
  A)
  \[312.5{}^\circ C\]                    done clear
  B)
  \[156{}^\circ C\] done clear
  C)
  \[500{}^\circ C\]           done clear
  D)
         \[624{}^\circ C\] done clear
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• question_answer94)
  A system S receives heat continuously from an electrical heater of power 10 W. The temperature of S becomes constant at \[50{}^\circ C\]when the surrounding temperature is \[20{}^\circ C\]. After the heater is switched off; S cools from \[35.1{}^\circ C\] to \[34.9{}^\circ C\] in 1 minute. The heat capacity of S is       
  A)
  \[100J/{}^\circ C\]          done clear
  B)
  \[300J/{}^\circ C\] done clear
  C)
  \[750J/{}^\circ C\]          done clear
  D)
         \[1500J/{}^\circ C\] done clear
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• question_answer95)
  An ideal Black-body at room temperature is thrown into a furnace. It is observed that
  A)
  initially it is the darkest body and at later times the brightest done clear
  B)
  it is the darkest body at all times done clear
  C)
  it cannot be distinguished at all times done clear
  D)
  initially it is the darkest body and at later times it cannot be distinguished done clear
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• question_answer96)
  A black body is at \[727{}^\circ \,C\]. It emits energy at a rate which is proportional to
  A)
  \[{{(1000)}^{4}}(b)\]    done clear
  B)
         \[{{(727)}^{2}}\] done clear
  C)
  \[727{{)}^{4}}\]          done clear
  D)
         \[{{(727)}^{2}}\] done clear
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• question_answer97)
  A spherical black body with a radius of 12 cm radiates 459 W power at 599 K. If the radius were halved and the temperature doubled, the power radiated in watt would be
  A)
  225       done clear
  B)
         459   done clear
  C)
  999       done clear
  D)
         1899 done clear
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• question_answer98)
  Three rods of identical cross-sectional area and made from the same metal from the sides of an isosceles traingle ABC, right-angled at B. The points A and B are maintained at temperatures T and \[(\sqrt{2})\] T respectively. In the steady state, the temperature of the point C is \[{{T}_{c}}\]. Assuming that only heat conduction takes place, \[{{T}_{c}}/T\]is  
  A)
  \[\frac{1}{2\left( \sqrt{2}-1 \right)}\]      done clear
  B)
  \[\frac{3}{\sqrt{2}+1}\] done clear
  C)
  \[\frac{1}{\sqrt{3}\left( \sqrt{2}-1 \right)}\] done clear
  D)
         \[\frac{1}{\sqrt{2}+1}\] done clear
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• question_answer99)
  Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are \[{{\operatorname{K}}_{1}} and {{K}_{2}}\]. The thermal conductivity of the composite rod will be :
  A)
  \[\frac{3({{K}_{1}}+{{K}_{2}})}{2}\]   done clear
  B)
         \[{{K}_{1}}+{{K}_{2}}\] done clear
  C)
  \[2\left( {{K}_{1}}+{{K}_{2}} \right)\]               done clear
  D)
  \[\frac{{{K}_{1}}+{{K}_{2}}}{2}\] done clear
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• question_answer100)
  A large cylindrical rod of length L is made by joining two identical rods of copper and steel of length I- each. The rods are completely insulated from the surroundings. If the free end of copper rod is maintained at \[100{}^\circ C\]band that of steel at \[9{}^\circ C\]then the temperature of junction is (Thermal conductivity of copper is 9 times that of steel)                 
  A)
  \[99{}^\circ C\]             done clear
  B)
         \[59{}^\circ C\] done clear
  C)
  \[19{}^\circ C\]                         done clear
  D)
  \[67{}^\circ C\] done clear
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