We consider a thermodynamic system. If ∆U represents the increase in its internal energy and W, the work done by the system; which of the following statements are true?

∆U=-W in an isothermal process

∆U=W in an isothermal process

∆U=-W in an adiabatic process

Assertion: The temperature of a gas does not change, when it undergoes an adiabatic expansion.

Reason: During an adiabatic process, heat energy is exchanged between a system and its surrounding.

Both assertion and reason are true and the reason is the correct explanation of the assertion

Both assertion and reason are true but the reason is not a correct explanation of the assertion

Assertion is true but the reason is false

Both assertion and reason are false

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1.	We consider a thermodynamic system. If ∆U represents the increase in its internal energy and W, the work done by the system; which of the following statements are true?
A.	∆U=-W in an isothermal process
B.	∆U=W in an isothermal process
C.	∆U=-W in an adiabatic process
D.	∆U=W in an adiabatic process
Answer» D. ∆U=W in an adiabatic process

Discussion

2.	Assertion: The temperature of a gas does not change, when it undergoes an adiabatic expansion.
A.	Reason: During an adiabatic process, heat energy is exchanged between a system and its surrounding.
B.	Both assertion and reason are true and the reason is the correct explanation of the assertion
C.	Both assertion and reason are true but the reason is not a correct explanation of the assertion
D.	Assertion is true but the reason is false
E.	Both assertion and reason are false
Answer» E. Both assertion and reason are false

Discussion

3.	Internal energy change, when a system goes from state A and B is 40 kJ mole-1. If the system goes from A and B by a reversible path and returns to state A by an irreversible path, what would be the net change in internal energy?
A.	40 kJ
B.	Greater than 40 kJ
C.	Later than 40 kJ
D.	Zero
Answer» E.

Discussion

4.	An ideal gas heat engine is operating between 227°C and 127°C. It absorbs 104 J of heat at the higher temperature. The amount of heat converted into work is?
A.	2000 J
B.	4000 J
C.	8000 J
D.	5600 J
Answer» B. 4000 J

Discussion

5.	A monoatomic ideal gas, initially at temperature T1 is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T2 by releasing the piston suddenly. L1 and L2 are the lengths of the gas column before and after expansion respectively, then T1/T2 is given by?
A.	(L1/L2)(2/3)
B.	L1/L2
C.	L2/L1
D.	(L2/L1)(2/3)
Answer» E.

Discussion

Explore topic-wise MCQs in Engineering Physics Questions and Answers.

We consider a thermodynamic system. If ∆U represents the increase in its internal energy and W, the work done by the system; which of the following statements are true?

Assertion: The temperature of a gas does not change, when it undergoes an adiabatic expansion.

Internal energy change, when a system goes from state A and B is 40 kJ mole-1. If the system goes from A and B by a reversible path and returns to state A by an irreversible path, what would be the net change in internal energy?

An ideal gas heat engine is operating between 227°C and 127°C. It absorbs 104 J of heat at the higher temperature. The amount of heat converted into work is?