question_answer4) A wire of length L is drawn such that its diameter is reduced to half of its original diameter. If the initial resistance of the wire were 10\[\frac{1}{2\pi }\sqrt{\frac{k}{m}}\], its new resistance would be:
question_answer5) A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 kV, its kinetic energy will be:
question_answer7) In an ideal parallel LC circuit, the capacitor is charged by connecting it to a DC source which is then disconnected. The current in the circuit:
question_answer9) A radioactive substance decays to 1/16th of its initial activity in 40 days. The half-life of the radioactive substance expressed in days is:
question_answer10) A neutron makes a head-on elastic collision with a stationary deuteron. The fractional energy loss of the neutron in the collision is:
question_answer12) Two small drops of mercury, each of radius R coalesce to form a single large drop. The ratio of the total surface energies before and after the change is:
question_answer13) A black body, at a temperature of \[227{}^\circ C\], radiates heat at a rate of 20 cal\[{{T}_{2}}>{{T}_{1}}\]. When its temperature is raised to \[727{}^\circ C\], the heat radiated by it in cal \[3q/{{\varepsilon }_{0}}\] will be closet to :
question_answer16) A double slit experiment is performed with light of wavelength 500 nm. A thin film of thickness 2\[y\]m and refractive index 1.5 is introduced in the path of the upper beam. The location of the central maximum will:
question_answer19) Three charges are placed at the vertices of an equilateral triangle of side a as shown in the following figure. The force experienced by the charge placed at the vertex A in a direction normal to BC is:
question_answer20) A capacitor of capacitance \[{{h}^{1/2}}\] is connected in the tank circuit of an oscillator oscillating with a frequency of 1 kHz, If the current flowing in the circuit is 2 mA, the voltage across the capacitor will be:
question_answer21) The earths magnetic field at a given point is \[0.5\,\times {{10}^{-5}}\,Wb\,\,{{m}^{-2}}\]. This field is to be annulled by magnetic induction at the centre of a circular conducting loop of radius 5.0 cm. The current required to be flown in the loop is nearly:
question_answer22) A frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as:
question_answer23) Shown below are the black body radiation curves at temperatures \[{{T}_{1}}\] and \[{{T}_{2}}({{T}_{2}}>{{T}_{1}})\]. Which of the following plots is correct?
question_answer25) In an experiment of find the focal length of a concave mirror, a graph is drawn between the magnitudes of u and v. The graph looks like:
question_answer27) An electron is travelling along the \[[{{M}^{-2}}L{{T}^{-2}}{{A}^{-1}}]\]-direction. It encounters a magnetic field in the \[[ML{{T}^{-2}}{{A}^{-2}}]\]-direction. Its subsequent motion will be:
A)
straight line along the \[[ML{{T}^{-1}}{{A}^{-1}}]\]-direction
question_answer29) A body starting from rest moves along a straight line with a constant acceleration. The variation of speed (v) with distance (i) I represented by the graph:
question_answer30) A rectangular loop carrying a current \[{{\beta }^{-}}\]is situated near a long straight wire carrying a steady current \[+\frac{G{{M}_{e}}m}{R}=\frac{1}{2}mv_{e}^{2}\] . The wire is parallel to one of the sides of the loop and is in the plane of the loop as shown in the figure. Then, the current loop will:
question_answer31) A ball is thrown vertically upwards. Which the following plots represents the speed-tin graph of the ball during its flight if the l resistance is not ignored?
question_answer32) Radioactive nuclei that are injected into a patient collected at certain sites within its body, undergoing radioactive decay and emitting electromagnetic radiation. These radiations can then be recorded by a detector. This procedure provides an important diagnostic tools called:
question_answer33) In a material medium, when a positron meets an electron both the particles annihilate leading to the emission of two gamma ray photons. This process forms the basis of an important diagnostic procedure called:
question_answer34) An astronaut is looking down on earths surface from a space shuttle at an altitude of 400 km. Assuming that the astronauts pupil diameter is 5 mm and the wavelength of visible light is 500 nm, the astronaut will be able to resolve linear objects of the size of about:
question_answer35) An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0 km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicentre of the earthquake is located at a distance of about:
question_answer36) A lead shot of a 1mm diameter falls through a long column of glycerine. The variation of its velocity v with distance covered is represented by:
question_answer38) In short wave communication waves of which of the following frequencies will be reflected back by the ionospheric layer having electron density 1011 per m3?
question_answer39) In the following common emitter configuration an n- p- n transistor with current gain \[\Omega \] -100 is used. The output voltage of the amplifier will be
question_answer42) Assertion: The earth is slowing down and as a result the moon is coming nearer to it. Reason: The angular momentum of the earth moon system is not conserved.
question_answer45) Assertion: The resistivity of a semiconductor increases with temperature. Reason: The atoms of a semiconductor vibrate with larger amplitude at higher temperatures thereby increasing its resistivity.
question_answer46) Assertion: The Coulomb force is the dominating force in the universe. Reason: The Coulomb force is weaker than the gravitational force.
question_answer47) Assertion: The length of the day is slowly increasing. Reason: The dominant effect causing a slowdown in the rotation of the earth is the gravitational pull of other planets in the solar system.
question_answer48) Assertion: Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate. Reason: According to classical physics all moving electrons radiate.
question_answer49) Assertion: The possibility of an electric bulb fusing is higher at the time of switching ON and OFF. Reason: Inductive effects produce a surge at the time of switch-OFF and switch-ON.
question_answer51) Assertion: A beam of charged particles is employed in the treatment of cancer. Reason: Charged particles on passing through a material medium lose their energy by causing ionization of the atoms along their path.
question_answer52) Assertion: When a beetle moves along the sand within a few tens of centimeters of a sand scorpion, the scoprion immediately turns towards the beetle and dashes towards it. Reason: When a beetle disturbs the sand sends pulses along the sands surface. One of plates is longitudinal while the other set is transverse.
question_answer53) Assertion: When a bottle of cold carbonated drink is opened, a slight fog forms around t opening. Reason: Adiabatic expansion of the gas causes lowering of temperature a condensation of water vapors.
question_answer56) Assertion: It is hotter over the top of a fire than at the same distance on the sides. Reason: Air surrounding the fire conducts more heat upwards.
question_answer57) Assertion: The amplitude of an oscillating pendulum decreases gradually with time. Reason: The frequency of the pendulum decreases with time.
question_answer58) Assertion: Microwave communication is preferred over optical communication. Reason: Microwaves provide large number of channels and band width compared to optical signals.
question_answer60) Assertion: In high latitudes one sees colorful curtains of light hanging down from high altitudes. Reason: The high energy charged particles from the sun are deflected to Polar Regions by the magnetic field of the earth.
question_answer70) On dissolving moderate amount of sodium metal in liquid \[C{{u}_{2}}O\] at low temperature, which one of the following does not occur?
A)
Blue colored solution is obtained
doneclear
B)
\[FeS\] ions are formed in the solution
doneclear
C)
Liquid \[Co\] becomes good conductor of electricity
question_answer73) In the extraction of copper from its sulphide ore, the metal is formed by reduction of \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}NHC{{H}_{3}}\] with:
question_answer90) One gram sample of \[2{{H}_{2}}(g)+{{O}_{2}}(g)\xrightarrow{{}}2{{H}_{2}}O(l)\] is decomposed in a bomb calorimeter. The temperature of the calorimeter increases by 6.12K. The heat capacity of the system is 1.23 kJ/g/deg. What is the molar heat of decomposition for\[2Fe(s)+{{O}_{2}}(g)+4{{H}^{+}}(aq)\xrightarrow{{}}\]?
question_answer100) The potential energy diagram for a reaction \[MnO_{4}^{-}\] is given below \[Mn{{O}_{2}}\] of the reaction corresponds to the energy:
question_answer101) Assertion: Solution of \[Mn{{O}_{2}}\] in water is intensely coloured. Reason Oxidation state of \[M{{n}_{2}}{{O}_{7}}\] in \[Mn{{O}_{2}}\] is \[M{{n}_{2}}{{O}_{7}}\]:
question_answer108) Assertion: Benzyl bromide when kept in acetone water it produces benzyl alcohol. Reason The reaction follows \[Cl{{O}_{2}}\] mechanism.
question_answer110) Assertion: Alkyl benzene is not prepared by Friedel-Crafts alkylation of benzene. Reason Alkyl halides are less reactive than acyl halides.
question_answer112) Assertion: Tran5-2-butene on reaction with \[NOCl\] gives meso-2, 3-dibromobutane. Reason The reaction involves \[NC{{l}_{3}}\]-addition of bromine.
question_answer113) Assertion: \[{{N}_{2}}{{O}_{4}}\]3-dihydroxy cyclohexane exists in boat conformation. Reason In the chair form, there will not be hydrogen bonding between the two hydroxyl groups.
question_answer114) Assertion: The increases in internal energy \[N{{H}_{3}}\] for the vaporization of one mole of water at 1 atm and 373 K is zero. Reason For all isothermal processes \[N{{a}^{+}}\].
question_answer115) Assertion: \[N{{H}_{3}}\] is more soluble in \[CO\] than in plain water. Reason Carbonate is a weak base and reacts with the \[N{{H}_{3}}\] from the strong acid, causing the barium salt to dissociate.
question_answer116) Assertion: \[{{C}_{2}}O_{4}^{2-}\] and \[C{{u}_{2}}{{(SCN)}_{2}}\] are almost the same for the reaction, \[C{{u}_{2}}O\] Reason All reactants and products are gases.
question_answer118) Assertion: Increasing pressure on pure water decreases its freezing point. Reason Density of water is maximum at \[C{{u}_{2}}{{I}_{2}}\].
question_answer119) Assertion: The micelle formed by sodium stearate in water has \[C{{u}_{2}}C{{O}_{3}}\] groups at the surface. Reason Surface tension of water is reduced by the addition of stearate.
question_answer142) Which fact suggests that most oxygen is transported from lungs to the tissue combined with haemoglobin rather than dissolved in blood plasma?
A)
\[{{O}_{2}}\] carrying capacity of whole blood is much higher than that of plasma and \[{{O}_{2}}\] content of blood leaving the lungs is greater than that of blood entering the lungs
doneclear
B)
Haemoglobin can combine with \[{{O}_{2}}\]
doneclear
C)
Oxyhaemoglobin can dissociate into haemoglobin and \[{{O}_{2}}\]
doneclear
D)
Increase in \[C{{O}_{2}}\] concentration decreases the \[{{O}_{2}}\] affinity of haemoglobin
question_answer145) A person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant object in his case will be formed:
question_answer161) Assertion: Mast cells in the human body release excessive amounts of inflammatory chemicals which cause allergic reactions. Reason: Allergens in the environment on reaching human body stimulate mast cells in certain individuals
question_answer162) Assertion: Use of fertilizers greatly enhances crop productivity. Reason: Irrigation is very important in increasing crop productivity.
question_answer163) Assertion: Smaller the organism higher the rate of metabolism per gram weight. Reason: The heart rate of a six month baby is much higher than that of an old person.
question_answer166) Assertion: Organochlorine pesticides are organic compounds that have been chlorinated. Reason: Fenitrothion is one of the organochlorine pesticides.
question_answer167) Assertion: Holoblastic cleavage with almost equal sized blastomeres is a characteristic of placental animals. Reason: Eggs of most mammals, including human, are of centrolecithal type.
question_answer168) Assertion: Inhabitants close to very busy airports are likely to experience health hazards. Reason: Sound level of jet aeroplanes usually exceeds 160 dB.
question_answer169) Assertion: All birds, except the ones like koel (cuckoo) build nests for retiring and taking rest during night time (day time for nocturnal). Reason: Koel lays its eggs in the nests of tailor bird.
question_answer170) Assertion: Old age is not an illness. It is a continuation of life with decreasing capacity for adaptation. Reason: Cessation of mitosis is a normal genetically programmed event.
question_answer172) Assertion: In plant tissue culture, somatic embryos can be induced from any plant cell. Reason: Any viable plant cell can differentiate into somatic embryos.
question_answer174) Assertion: Water and mineral uptake by root hairs from the soil occurs through apoplast until it reaches endodermis. Reason: Casparian strips in endodermis are suberized.
question_answer175) Assertion: Long distance flow of photo assimilates in plants occurs through sieve tubes. Reason: Mature sieve tubes have parietal cytoplasm and perforated sieve plates.
question_answer176) Assertion: Many visitors to the hills suffer from skin and respiratory allergy problems. Reason: Conifer trees produce a large quantity of wind-borne pollen grains.
question_answer177) Assertion: Yeasts such as Saccharomyces cerevisiae are used in baking industry. Reason: Carbon dioxide produced during fermentation causes bread dough to rise by thermal expansion.
question_answer178) Assertion: In a food chain members of successive higher levels are fewer in number. Reason: Number of organisms at any trophic level depends upon the availability of organisms which serve as food at the lower level.
question_answer179) Assertion: Tropical rain forests are disappearing fast from developing countries such as India. Reason: No value is attached to these forests because these are poor in biodiversity.
question_answer180) Assertion: Leaf butterfly and stick insect show mimicry to dodge their enemies. Reason: Mimicry is a method to acquire body colour of blinding with the surrounding.