Solved papers for NEET Physics Transmission of Heat NEET PYQ-Transmission Of Heat

done NEET PYQ-Transmission Of Heat Total Questions - 23

• question_answer1) The radiant energy from the sun, incident normally at the surface of earth is \[20\text{ }kcal/{{m}^{2}}\,\min \]. What would have been the radiant energy, incident normally on the earth, if the sun had a temperature, twice of the present one?                                                                                                                                                       [AIPMT 1998]
  A)
   \[160\text{ }kcal/{{m}^{2}}\min \]
  done clear
  B)
        \[40\text{ }kcal/{{m}^{2}}\min \]
  done clear
  C)
   \[320\text{ }kcal/{{m}^{2}}\min \]
  done clear
  D)
        \[80\text{ }kcal/{{m}^{2}}\min \]
  done clear
  View Answer play_arrow

• question_answer2) Which one of the following processes depends on gravity?                                       [AIPMT 2000]
  A)
   Conduction
  done clear
  B)
                    Convection      
  done clear
  C)
   Radiation
  done clear
  D)
                    None
  done clear
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• question_answer3)   The wavelength corresponding to maximum intensity of radiation emitted by a source at temperature 2000 K is \[\lambda ,\] then what is the wavelength corresponding to maximum intensity of radiation at temperature 3000 K?   [AIPMT 2001]
  A)
   \[\frac{2}{3}\lambda \] 
  done clear
  B)
                   \[\frac{16}{81}\lambda \]
  done clear
  C)
   \[\frac{81}{16}\lambda \]
  done clear
  D)
                    \[\frac{4}{3}\lambda \]
  done clear
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• question_answer4) Rate of heat flow through a cylindrical rod is \[{{H}_{1}}\]. Temperatures of ends of rod are \[{{T}_{1}}\] and \[{{T}_{2}}\]. If all the dimensions of rod become double and temperature difference remains same and rate of heat flow becomes \[{{H}_{2}}\]. Then:                                                                              [AIPMT 2001]
  A)
   \[{{H}_{2}}=2{{H}_{1}}\]     
  done clear
  B)
        \[{{H}_{2}}=\frac{{{H}_{1}}}{2}\]   
  done clear
  C)
   \[{{H}_{2}}=\frac{{{H}_{1}}}{4}\]   
  done clear
  D)
        \[{{H}_{2}}=4{{H}_{1}}\]
  done clear
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• question_answer5) Which of the following is close to an ideal black body:                                           [AIPMT 2002]
  A)
   black lamp
  done clear
  B)
                                cavity maintained at constant temperature
  done clear
  C)
        platinum black  
  done clear
  D)
        a lamp of charcoal heated to high temperature
  done clear
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• question_answer6) Wien's displacement law expresses relation between:                       [AIPMT 2002]
  A)
   wavelength corresponding to maximum  energy and absolute temperature
  done clear
  B)
        radiated energy and wavelength
  done clear
  C)
   emissive power and temperature  
  done clear
  D)
        colour of light and temperature
  done clear
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• question_answer7) The unit of Stefan's constant is:                                                                                           [AIPMT 2002]
  A)
   \[W-{{m}^{2}}-{{K}^{4}}\] 
  done clear
  B)
        \[W-{{m}^{3}}/{{K}^{4~}}\]
  done clear
  C)
   \[W/{{m}^{2}}-K\]
  done clear
  D)
                    \[W/{{m}^{2}}-{{K}^{4}}\]
  done clear
  View Answer play_arrow

• question_answer8) Consider two rods of same length and differed specific heats\[({{s}_{1}},\,\,{{s}_{2}}),\] thermal conductivity \[({{K}_{1}},\text{ }{{K}_{2}})\] and areas of cross section \[({{A}_{1}},\text{ }{{A}_{2}})\] and both having temperatures \[({{T}_{1}},\text{ }{{T}_{2}})\] at their ends. If their rate of loss of heat due to conduction is equal, then :
  A)
   \[{{K}_{1}}{{A}_{1}}={{K}_{2}}{{A}_{2}}\]
  done clear
  B)
        \[\frac{{{K}_{1}}\,{{A}_{1}}}{{{s}_{1}}},\frac{{{K}_{2}}{{A}_{2}}}{{{s}_{2}}}\]
  done clear
  C)
   \[{{K}_{2}}{{A}_{1}}={{K}_{1}}{{A}_{2}}\]
  done clear
  D)
                    \[\frac{{{K}_{2}}{{A}_{1}}}{{{s}_{2}}}=\frac{{{K}_{1}}{{A}_{2}}}{{{s}_{1}}}\]
  done clear
  View Answer play_arrow

• question_answer9) Consider a compound slab consisting of two different materials having equal thickneses and thermal conductivities K and 2K, respectively. The equivalent thermal conductivity of the slab is:                                 [AIPMT 2003]
  A)
         \[3\,K\]            
  done clear
  B)
       \[\frac{4}{3}K\]
  done clear
  C)
   \[\frac{2}{3}K\]           
  done clear
  D)
        \[\sqrt{2}\,K\]
  done clear
  View Answer play_arrow

• question_answer10) If \[{{\lambda }_{m}}\] denotes the wavelength at which the radiative emission from a black body at a temperature T K is maximum, then:                                                                                                             [AIPMT (S) 2004]
  A)
   \[{{\lambda }_{m}}\,\propto \,\,{{T}^{4}}\]                
  done clear
  B)
        \[{{\lambda }_{m}}\] is independent of T
  done clear
  C)
        \[{{\lambda }_{m}}\propto \,\,T\]          
  done clear
  D)
        \[{{\lambda }_{m}}\propto \,\,{{T}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer11) Which of the following circular rods, (given radius r and length l) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?                             [AIPMT (S) 2005]
  A)
    \[r=2{{r}_{0}};\,l=2{{l}_{0}}\]
  done clear
  B)
        \[r=2{{r}_{0}};\,l={{l}_{0}}\]
  done clear
  C)
   \[r={{r}_{0}};\,l={{l}_{0}}\]
  done clear
  D)
                    \[r={{r}_{0}};\,l=2{{l}_{0}}\]
  done clear
  View Answer play_arrow

• question_answer12) A black body at \[{{1227}^{o}}C\] emits radiations with maximum intensity at a wavelength of \[5000\text{ }{\AA}\]. If the temperature of the body is increased by \[{{1000}^{o}}C,\] the maximum intensity will be observed at:                                                                                                                                                          [AIPMT (S) 2006]
  A)
   \[4000\text{ }{\AA}\]
  done clear
  B)
                    \[5000\text{ }{\AA}\]
  done clear
  C)
   \[6000\text{ }{\AA}\]
  done clear
  D)
                    \[3000\text{ }{\AA}\]
  done clear
  View Answer play_arrow

• question_answer13) Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature \[t{}^\circ C,\] the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is:                                                                                                                                     [AIPMT (S) 2007]
  A)
   \[\frac{4\pi {{r}^{2}}\sigma \,{{t}^{4}}}{{{R}^{2}}}\]        
  done clear
  B)
        \[\frac{{{r}^{2}}\,\sigma \,{{(t+273)}^{4}}}{4\pi {{R}^{2}}}\]
  done clear
  C)
   \[\frac{16\,{{\pi }^{2}}\,{{r}^{2}}\,\sigma {{t}^{4}}}{{{R}^{2}}}\]
  done clear
  D)
                    \[\frac{{{r}^{2}}\,\sigma \,{{(t+273)}^{4}}}{{{R}^{2}}}\]
  done clear
  View Answer play_arrow

• question_answer14) A black body is at \[727{}^\circ C\]. It emits energy at a rate which is proportional to:               [AIPMT (S) 2007]
  A)
  \[{{(727)}^{2}}\]
  done clear
  B)
                    \[{{(1000)}^{4}}\]
  done clear
  C)
   \[{{(1000)}^{2}}\]
  done clear
  D)
                    \[{{(727)}^{4}}\]
  done clear
  View Answer play_arrow

• question_answer15) The particle executing simple harmonic motion has a kinetic energy \[{{K}_{0}}\,co{{s}^{2}}\,\omega t\]. The maximum values of the potential energy and the total energy are respectively:                                       [AIPMT (S) 2007]
  A)
   0 and \[2\text{ }{{K}_{0}}\]
  done clear
  B)
                    \[\frac{{{K}_{0}}}{2}\] and \[{{K}_{0}}\]
  done clear
  C)
   \[{{K}_{0}}\] and \[2{{K}_{0}}\]
  done clear
  D)
                    \[{{K}_{0}}\] and \[{{K}_{0}}\]
  done clear
  View Answer play_arrow

• question_answer16) A slab of stone of area of \[0.36\,{{m}^{2}}\] 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 of fusion of ice \[=3.36\times {{10}^{5}}J\,k{{g}^{-1}}\])           [AIPMT (M) 2012]
  A)
   \[1.24J/m/s/{}^\circ C\]
  done clear
  B)
        \[1.29\text{ }J/m/s/{}^\circ C\]
  done clear
  C)
    \[2.05\text{ }J/m/s/{}^\circ C\]
  done clear
  D)
   \[1.02\text{ }J/m/s/{}^\circ C\]
  done clear
  View Answer play_arrow

• question_answer17) If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q?                                                                                                             [AIPMT (S) 2012]
  A)
   \[Q/4\pi {{R}^{2}}\sigma \]     
  done clear
  B)
        \[{{(Q/4\pi {{R}^{2}}\sigma )}^{-1/2}}\]
  done clear
  C)
   \[{{(4\pi {{R}^{2}}Q/\sigma )}^{1/4}}\]
  done clear
  D)
        \[{{(Q/4\pi {{R}^{2}}\sigma )}^{1/4}}\]
  done clear
  View Answer play_arrow

• question_answer18) A piece of iron is heated in a flame. If first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using                                          [NEET 2013]
  A)
   Stefan's law
  done clear
  B)
   Wien's displacement law
  done clear
  C)
   Kirchoff's law
  done clear
  D)
   Newton's law of cooling
  done clear
  View Answer play_arrow

• question_answer19) Certain quantity of water cools from \[70{}^\circ C\] to \[60{}^\circ C\] in the first 5 min and to \[54{}^\circ C\] in the next 5 min. The temperature of the surroundings is                                                                                 [NEET 2014]
  A)
   \[45{}^\circ C\]           
  done clear
  B)
        \[20{}^\circ C\]
  done clear
  C)
   \[42{}^\circ C\]           
  done clear
  D)
        \[10{}^\circ C\]
  done clear
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• question_answer20) On observing light from three different stars P, Q and R, it was found that intensity of violet colour is maximum in the spectrum of P, the intensity of green colour is maximum in the spectrum of R and the intensity of red colour is maximum in the spectrum of Q. If \[{{T}_{P}},{{T}_{Q}}\] and \[{{T}_{R}}\] are the respective absolute temperatures of P, Q and R, then it can be concluded from the above observations that                                                                                   [NEET  2015]
  A)
   \[{{T}_{P}}>{{T}_{Q}}>{{T}_{R}}\]
  done clear
  B)
        \[{{T}_{P}}>{{T}_{R}}>{{T}_{Q}}\]
  done clear
  C)
   \[{{T}_{P}}<{{T}_{R}}<{{T}_{Q}}\]
  done clear
  D)
        \[{{T}_{P}}<{{T}_{Q}}<{{T}_{R}}\]
  done clear
  View Answer play_arrow

• question_answer21) 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                                                                                                  [NEET  2015]
  A)
   44.0 J/s                       
  done clear
  B)
   16.8 J/s
  done clear
  C)
   8.0 J/s                
  done clear
  D)
        4.0 J/s
  done clear
  View Answer play_arrow

• question_answer22) Two metal wires of identical dimensions are connected in series. If \[{{\sigma }_{1}}\] and \[{{\sigma }_{2}}\] are the conductivities of the metal wires respectively, the effective conductivity of the combination is    [NEET (Re) 2015]
  A)
   \[\frac{2{{\sigma }_{1}}{{\sigma }_{2}}}{{{\sigma }_{1}}+{{\sigma }_{2}}}\]
  done clear
  B)
        \[\frac{{{\sigma }_{1}}+{{\sigma }_{2}}}{2{{\sigma }_{1}}{{\sigma }_{2}}}\]
  done clear
  C)
    \[\frac{{{\sigma }_{1}}+{{\sigma }_{2}}}{{{\sigma }_{1}}{{\sigma }_{2}}}\] 
  done clear
  D)
         \[\frac{{{\sigma }_{1}}{{\sigma }_{2}}}{{{\sigma }_{1}}+{{\sigma }_{2}}}\]
  done clear
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• question_answer23) The power radiated by a black body is P and it radiates maximum energy at wavelength, \[{{\lambda }_{0}}\]. If the temperature of the black body is now changed so that it radiates maximum energy at wavelength \[\frac{3}{4}{{\lambda }_{0}}\], the power radiated by it becomes \[\text{nP}\]. The value of n is                                                                                                                                         [NEET - 2018]
  A)
   \[\frac{256}{81}\]     
  done clear
  B)
        \[\frac{4}{3}\]
  done clear
  C)
   \[\frac{3}{4}\]                       
  done clear
  D)
        \[\frac{81}{256}\]
  done clear
  View Answer play_arrow