Heat & Thermodynamics · JEE Main previous year questions

2012 4 questions

1. Q412012 · 26 May 2012 · Shift 1

   An ideal monatomic gas with pressure $P$, volume $V$ and temperature $T$ is expanded isothermally to a volume $2V$ and a final pressure $P_i$. If the same gas is expanded adiabatically to a volume $2V$, the final pressure is $P_a$. The ratio $\frac{P_a}{P_i}$ is

   1. A.$2^{-1/3}$
   2. B.$2^{1/3}$
   3. C.$2^{2/3}$
   4. D.$2^{-2/3}$
   Show answer

   Answer: D

2. Q582012 · 26 May 2012 · Shift 1

   The door of a working refrigerator is left open in a well insulated room. The temperature of air in the room will

   1. A.decrease
   2. B.increase in winters and decrease in summers
   3. C.remain the same
   4. D.increase
   Show answer

   Answer: D

3. Q412012 · 12 May 2012 · Shift 1

   A given ideal gas with $\gamma =\frac{C_p}{C_v}=1.5$ at a temperature $T$. If the gas is compressed adiabatically to one-fourth of its initial volume, the final temperature will be

   1. A.$2\sqrt{2}T$
   2. B.$4T$
   3. C.$2T$
   4. D.$8T$
   Show answer

   Answer: C

4. Q442012 · 7 May 2012 · Shift 1

   This question has Statement 1 and Statement 2. Of the four choices given after the Statements, choose the one that best describes the two Statements. Statement 1: In an adiabatic process, change in internal energy of a gas is equal to work done on/by the gas in the process. Statement 2: The temperature of a gas remains constant in an adiabatic process.

   1. A.Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation of Statement 1.
   2. B.Statement 1 is true, Statement 2 is false.
   3. C.Statement 1 is false, Statement 2 is true.
   4. D.Statement 1 is false, Statement 2 is true, Statement 2 is not a correct explanation of Statement 1.
   Show answer

   Answer: B