A lead bullet penetrates into a solid object and from Class Physics Thermodynamics

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NEET Physics : Thermodynamics

Multiple Choice Questions

61.

A thermodynamic process is carried out from an original state D to an intermediate state E by the linear process shown in figure

The total work is done by the gas from D to E to F is

  • 100 J

  • 800 J

  • 300 J

  • 250 J



62.

When an ideal monoatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is

  • 2 / 5

  • 3 / 5

  • 3 / 7

  • 5 / 7



63.

The slope of isothermal and adiabatic curves are related as

  • isothermal curve slope= adiabatic curve slope

  • isothermal curve slope = γ × adiabatic curve slope

  • adiabatic curve slope = γ× isothermal curve slope

  • adiabatic curve slope =12× isothermal curve slope



64.

A lead bullet penetrates into a solid object and melts. Assuming that 50% of its kinetic energy was used to heat it, the initial speed of the bullet is (the initial temperature of the bullet is 25oC and its melting point is 300°C). Latent heat of fusion of lead= 2.5 x 104 J/kg and specific heat capacity of lead= 125 J/kg-K

  • 100 m/s

  • ≈ 490 m/s

  • 520 m/s

  • 360 m/s



65.

Assertion:  In an isolated system the entropy increases. 

Reason:  The process in an isolated system is adiabatic only.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



66.

Assertion:  The specific heat of a gas in an adiabatic process is zero and in an isothermal process is infinite.

Reason:  Specific heat of gas is directly proportional to change of heat in system and inversely proportional to change in temperature.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



67.

Assertion: It is not possible for a system, unaided by an external agency to transfer heat from a body at lower temperature to another body at a higher temperature.

Reason: It is not possible to violate the second law of thermodynamics

 

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



68.

3 mole of hydrogen is mixed with 1 mole of neon. The molar specific heat at constant pressure is

  • 9 R4

  • 9 R2

  • 13 R4

  • 13 R2



69.

The volume of an ideal gas is doubled in an isothermal process. Then, which of the following is true?

  • Work done by the gas is positive

  • Work done by the gas is negative

  • Internal energy of the system decreases

  • Internal energy of the system increases



70.

A Carnot engine operates with source at 127°C and sink at 27°C. If the source supplies 40 kJ of heat energy, the work done by the engine is

  • 30 kJ

  • 10 kJ

  • 4 kJ

  • 1 kJ



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