Assertion:  In free expansion of an ideal gas, the entr

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

161.

A certain gas is taken to the five states represented by dots in the graph. The plotted lines are isotherms. Order of the most portable speed νp of the molecules at these five states is

  • νp at 3  > νp at 1 = νp at 2 > νp at 4 = νp at 5

  • νp at 1 > νp at 2 =  νp at 3 > νp at 4 > νp at 5

  • νp at 3 > νp at 2 = νp at 4 > νp at 1 = νp at 5

  • insufficient information to predict the result


162.

Two heater wires, made of the same material and having the same length and the same radius, are first connected in series and then in parallel to a constant potential difference. If the rates of I heat produced in the two cases are Hs  and  HP respectively, then  Hs/HP  will be

  • 1/2

  • 2

  • 1/4

  • 4


163.

In an adiabatic change , the pressure and temperature of a monoatomic gas are relted as P ∝ TC, where C equals

  • 23

  • 52

  • 35

  • 53


164.

Assertion: Ferro magnetic substances become paramagnetic above Curie temperature.

Reason: Domains are destroyed at high 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


Advertisement
Advertisement

165.

Assertion:  In free expansion of an ideal gas, the entropy increases. 

Reason:  Entropy increases in all natural processes.

  • 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


A.

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

All natural processes occur in such a way that total entropy of the universe increase. The only heat transfer that could occur and leave and entropy of the universe unchanged is one that occurs between two objects which are at the same temperature - but that is not possible since no heat would transfer.

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. The total entropy of a system and its surroundings can remain constant in ideal cases where the system is in thermodynamic equilibrium or is undergoing a reversible process. In all process that occurs, including spontaneous processes, the total entropy of the system and its surroundings increases and the process is irreversible in the thermodynamic sense.


Advertisement
166.

By sucking through a straw, a student can reduce the pressure in his lungs to 750 mm of Hg ( densiy = 13.6 g/cm3). Using the straw, he can drink water from a glass upto a maximum depth of

  • 10 cm

  • 75 cm

  • 13.6 cm

  • 1.36 cm


167.

When you make ice cubes, the entropy of water

  • does not change

  • increase

  • decreases

  • may either increase or decrease depending on the process used


168.

A bimetallic strip consists of metals X and Y. It is mounted rigidly at the base as shown. The metal X has a higher coefficient of expansion compared to that for metal Y. When the bimetallic strip is placed in a cold bath

  • it will bend towards the right

  • it will bend towards the left

  • it will not bend but shrink

  • it will neither bend or shrink


Advertisement
169.

Assertion:  In an isolated system the entropy increases. 

Reason: The processes in an isolated system are adiabatic.

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

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

  • If assertion is true, but reason is false

  • Both assertion and reason are false statements


170.

Assertion:  The Carnot cycle is useful in understanding the performance of heat engines. 

Reason:  The Carnot cycle provides a way of determining the maximum possible efficiency achievable with reservoirs of given temperatures.

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

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

  • If assertion is true, but reason is false

  • Both assertion and reason are false statements


Advertisement