# 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)
$160\text{ }kcal/{{m}^{2}}\min$

B)
$40\text{ }kcal/{{m}^{2}}\min$

C)
$320\text{ }kcal/{{m}^{2}}\min$

D)
$80\text{ }kcal/{{m}^{2}}\min$

• question_answer2) Which one of the following processes depends on gravity?                                       [AIPMT 2000]

A)
Conduction

B)
Convection

C)

D)
None

• 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)
$\frac{2}{3}\lambda$

B)
$\frac{16}{81}\lambda$

C)
$\frac{81}{16}\lambda$

D)
$\frac{4}{3}\lambda$

• 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)
${{H}_{2}}=2{{H}_{1}}$

B)
${{H}_{2}}=\frac{{{H}_{1}}}{2}$

C)
${{H}_{2}}=\frac{{{H}_{1}}}{4}$

D)
${{H}_{2}}=4{{H}_{1}}$

• question_answer5) Which of the following is close to an ideal black body:                                           [AIPMT 2002]

A)
black lamp

B)
cavity maintained at constant temperature

C)
platinum black

D)
a lamp of charcoal heated to high temperature

• question_answer6) Wien's displacement law expresses relation between:                       [AIPMT 2002]

A)
wavelength corresponding to maximum  energy and absolute temperature

B)

C)
emissive power and temperature

D)
colour of light and temperature

• question_answer7) The unit of Stefan's constant is:                                                                                           [AIPMT 2002]

A)
$W-{{m}^{2}}-{{K}^{4}}$

B)
$W-{{m}^{3}}/{{K}^{4~}}$

C)
$W/{{m}^{2}}-K$

D)
$W/{{m}^{2}}-{{K}^{4}}$

• 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)
${{K}_{1}}{{A}_{1}}={{K}_{2}}{{A}_{2}}$

B)
$\frac{{{K}_{1}}\,{{A}_{1}}}{{{s}_{1}}},\frac{{{K}_{2}}{{A}_{2}}}{{{s}_{2}}}$

C)
${{K}_{2}}{{A}_{1}}={{K}_{1}}{{A}_{2}}$

D)
$\frac{{{K}_{2}}{{A}_{1}}}{{{s}_{2}}}=\frac{{{K}_{1}}{{A}_{2}}}{{{s}_{1}}}$

• 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)
$3\,K$

B)
$\frac{4}{3}K$

C)
$\frac{2}{3}K$

D)
$\sqrt{2}\,K$

• 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)
${{\lambda }_{m}}\,\propto \,\,{{T}^{4}}$

B)
${{\lambda }_{m}}$ is independent of T

C)
${{\lambda }_{m}}\propto \,\,T$

D)
${{\lambda }_{m}}\propto \,\,{{T}^{-1}}$

• 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)
$r=2{{r}_{0}};\,l=2{{l}_{0}}$

B)
$r=2{{r}_{0}};\,l={{l}_{0}}$

C)
$r={{r}_{0}};\,l={{l}_{0}}$

D)
$r={{r}_{0}};\,l=2{{l}_{0}}$

• 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)
$4000\text{ }{\AA}$

B)
$5000\text{ }{\AA}$

C)
$6000\text{ }{\AA}$

D)
$3000\text{ }{\AA}$

• 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)
$\frac{4\pi {{r}^{2}}\sigma \,{{t}^{4}}}{{{R}^{2}}}$

B)
$\frac{{{r}^{2}}\,\sigma \,{{(t+273)}^{4}}}{4\pi {{R}^{2}}}$

C)
$\frac{16\,{{\pi }^{2}}\,{{r}^{2}}\,\sigma {{t}^{4}}}{{{R}^{2}}}$

D)
$\frac{{{r}^{2}}\,\sigma \,{{(t+273)}^{4}}}{{{R}^{2}}}$

• question_answer14) A black body is at $727{}^\circ C$. It emits energy at a rate which is proportional to:               [AIPMT (S) 2007]

A)
${{(727)}^{2}}$

B)
${{(1000)}^{4}}$

C)
${{(1000)}^{2}}$

D)
${{(727)}^{4}}$

• 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 $2\text{ }{{K}_{0}}$

B)
$\frac{{{K}_{0}}}{2}$ and ${{K}_{0}}$

C)
${{K}_{0}}$ and $2{{K}_{0}}$

D)
${{K}_{0}}$ and ${{K}_{0}}$

• 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)
$1.24J/m/s/{}^\circ C$

B)
$1.29\text{ }J/m/s/{}^\circ C$

C)
$2.05\text{ }J/m/s/{}^\circ C$

D)
$1.02\text{ }J/m/s/{}^\circ C$

• 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)
$Q/4\pi {{R}^{2}}\sigma$

B)
${{(Q/4\pi {{R}^{2}}\sigma )}^{-1/2}}$

C)
${{(4\pi {{R}^{2}}Q/\sigma )}^{1/4}}$

D)
${{(Q/4\pi {{R}^{2}}\sigma )}^{1/4}}$

• 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

B)
Wien's displacement law

C)
Kirchoff's law

D)
Newton's law of cooling

• 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)
$45{}^\circ C$

B)
$20{}^\circ C$

C)
$42{}^\circ C$

D)
$10{}^\circ C$

• 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)
${{T}_{P}}>{{T}_{Q}}>{{T}_{R}}$

B)
${{T}_{P}}>{{T}_{R}}>{{T}_{Q}}$

C)
${{T}_{P}}<{{T}_{R}}<{{T}_{Q}}$

D)
${{T}_{P}}<{{T}_{Q}}<{{T}_{R}}$

• 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

B)
16.8 J/s

C)
8.0 J/s

D)
4.0 J/s

• 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)
$\frac{2{{\sigma }_{1}}{{\sigma }_{2}}}{{{\sigma }_{1}}+{{\sigma }_{2}}}$

B)
$\frac{{{\sigma }_{1}}+{{\sigma }_{2}}}{2{{\sigma }_{1}}{{\sigma }_{2}}}$

C)
$\frac{{{\sigma }_{1}}+{{\sigma }_{2}}}{{{\sigma }_{1}}{{\sigma }_{2}}}$

D)
$\frac{{{\sigma }_{1}}{{\sigma }_{2}}}{{{\sigma }_{1}}+{{\sigma }_{2}}}$

• 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)
$\frac{256}{81}$

B)
$\frac{4}{3}$

C)
$\frac{3}{4}$

D)
$\frac{81}{256}$