Two samples A and B of a gas initially at the same pressure and temperature are compressed from volume V to V/2 (A isothermally and B adiabatically). The final pressure of A is
(1) Greater than the final pressure of B
(2) Equal to the final pressure of B
(3) Less than the final pressure of B
(4) Twice the final pressure of B
Initial pressure and volume of a gas are P and V respectively. First it is expanded isothermally to volume 4V and then compressed adiabatically to volume V. The final pressure of gas will be [Given : -
(1) 1P
(2) 2P
(3) 4P
(4) 8P
A thermally insulated rigid container contains an ideal gas heated by a filament of resistance 100 Ω through a current of 1A for 5 min . Then change in internal energy is -
(1) 0 kJ
(2) 10 kJ
(3) 20 kJ
(4) 30 kJ
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are -
(1) 80°C, 37°C
(2) 95°C, 28°C
(3) 90°C, 37°C
(4) 99°C, 37°C
An ideal monoatomic gas expands in such a manner that its pressure and volume can be related by equation . During this process, the gas is
(1) Heated
(2) Cooled
(3) Neither heated nor cooled
(4) First heated and then cooled
P-V diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be -
1. 4 R
2. 2.5 R
3. 3 R
4.
Following figure shows on adiabatic cylindrical container of volume V0 divided by an adiabatic smooth piston (area of cross-section = A) in two equal parts. An ideal gas is at pressure P1 and temperature T1 in left part and gas at pressure P2 and temperature T2 in right part. The piston is slowly displaced and released at a position where it can stay in equilibrium. The final pressure of the two parts will be (Suppose x = displacement of the piston)
(1) P2
(2) P1
(3)
(4)
Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300 K. The piston of A is free to move while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in A is 30 K, then the rise in temperature of the gas in B is
(1) 30 K
(2) 18 K
(3) 50 K
(4) 42 K
A system goes from A to B via two processes I and II as shown in figure. If ΔUI and ΔUII are the changes in internal energies in the processes I and II respectively, then
(1) ΔUII > ΔUI
(2) ΔUII < ΔUI
(3) ΔUI = ΔUII
(4) Relation between ΔUI and ΔUII can not be determined
A thermodynamic system is taken through the cycle PQRSP process. The net work done by the system is -
(1) 20 J
(2) – 20 J
(3) 400 J
(4) – 374 J