Free Printable Physics Unit 5 Test

1.

Work done on or by a gas, in general depends upon the:

a)

Initial state only

b)

Final state only

c)

Both initial & final states only

d)

Initial state, final state & the path

2.

A gas at STP is suddenly compressed to one-fourth of its original volume. If γ is supposed to be (3/2), then the final pressure is:

a)

$4\ atm$

b)

$\frac{3}{2}\ atm$

c)

8 atm

d)

$\frac{1}{4}\ atm$

3.

During the adiabatic expansion of 2 moles of a gas the internal energy of the gas is found to decrease by 4 joules. The work done during the process by gas will be equal to:

a)

2 joules

b)

-2 joules.

c)

4 joules

d)

-4 joules

4.

If R= universal gas constant, the amount of heat needed to raise the temperature of 2 moles of an ideal monoatomic gas from 300 K to 450 K when no work is done:

a)

100R

b)

300 R

c)

150R

d)

450R

5.

In pressure volume graph of an ideal gas cycle consisting of adiabatic and isothermal process. The adiabatic expansion is described by:

a)

AB

b)

BC

c)

CD

d)

DA

6.

The internal energy U is a unique function of any state because of change in U:

a)

Does not depend upon path

b)

Depends upon path

c)

Corresponds to an adiabatic process

d)

Corresponds to an isothermal process

7.

A system undergoes a change of state from (P1,V1,T1 ) to (P2,V2,T2 ) which of the following is true?

a)

ΔU=0 if T1=T2

b)

ΔU=+ ve if T1 < T2

c)

ΔU=-ve if T1 > T2

d)

All of these

8.

An ideal gas of mass m in a state A goes to another state B via three different processes as shown in fig. If Q1, Q2 and Q3 denote the heat absorbed by the gas along the three paths, then:

a)

$Q_1<Q_2<Q_3$

b)

$Q_1<Q_2=Q_3$

c)

$Q_1=Q_2>Q_3$

d)

$Q_1>Q_2>Q_3$

9.

The indicator diagrams representing maximum and minimum amount of work done are respectively:

a)

A and B

b)

B and C

c)

B and D

d)

C and D

10.

The change in internal energy of the system is positive if:

a)

System rapidly expands

b)

System rapidly compresses

c)

Temperature increases

d)

Both B and C

11.

The molar heat capacity of an ideal gas is greater at constant pressure than at constant volume because:

a)

Additional energy is needed for external work

b)

The molecules acquire greater K.E at constant pressure

c)

There are more molecular collisions at constant volume

d)

None of these

12.

If a system under goes a cyclic process, then which is true according to 1st law of thermodynamics?

a)

Q = W

b)

$\Delta U=0$

c)

$Q=\Delta U$

d)

Both A & B

13.

If $C_p=\frac{5R}{2}$ , Then $\gamma=\frac{C_p}{C_v}$ for the monoatomic gas is :

a)

7/2

b)

7/5

c)

5/4

d)

5/3

14.

The conversion of water into steam at 100 °C is:

a)

An isochoric process

b)

An adiabatic process

c)

Isothermal process

d)

Isobaric process

15.

In a thermodynamics process, the pressure of a fixed mass of the gas is changed in such a manner that the gas releases 20 J of heat and 8 J of work is done on the gas. If initially the internal energy of the gas was 30 J, then the final internal energy will be:

a)

2 J

b)

18 J

c)

42 J

d)

58 J

16.

1st law of thermodynamics for 1 mole of ideal gas undergoing isobaric process can be written as:

a)

$C_v\Delta T=\Delta U$

b)

$C_v\Delta T=C_p\Delta T+P\Delta V$

c)

$C_p\Delta T=C_v\Delta T+P\Delta V$

d)

$C_p\Delta T=P\Delta V$

17.

For hydrogen gas:

a)

$C_p=\frac{5}{2}R$

b)

$C_v=\frac{5}{2}R$

c)

$C_v\ is\ negligible$

d)

$C_v=\frac{7}{2}R$

18.

If $C_p-C_v=R$ and $\frac{C_p}{C_v}=\gamma$ , then which relation is correct

a)

$C_v=\frac{R}{\gamma-1}$

b)

$C_v=\frac{\gamma R}{\gamma-1}$

c)

$C_v=\frac{R^2}{\gamma}$

d)

$C_v=\frac{\gamma-1}{R}$

19.

100 W heater is used for 5 minutes to heat 500 g of water. What is the change in temperature of water? Specific heat capacity of water is 4.2 J/gC.

a)

140C

b)

40C

c)

0.2C

d)

14C

20.

In an adiabatic process, $PV^{\gamma}$ = constant; the value ‘ $\gamma$ ’ is

a)

$\frac{C_v}{C_p}$

b)

$1-\frac{R}{C_v}$

c)

$\frac{R}{C_v}-1$

d)

$1+\frac{R}{C_v}$

21.

The heat capacity at constant volume and the heat capacity at constant pressure have different values because:

a)

Heat increases the temperature at constant volume but not at constant pressure

b)

Heat increases the temperature at constant pressure but not at constant volume

c)

The system does work at constant volume but not at constant pressure

d)

The system does work at constant pressure but not at constant volume

22.

In which process the entire of heat supplied to the gas is converted to the internal energy of the gas?

a)

Isochoric process

b)

Isobaric process

c)

Isothermal process

d)

Adiabatic process

23.

A sample of an ideal gas taken through a closed cycle is presented by the P-V diagram. The process 1-2 is perfectly isothermal. Which of the following is true about the change in internal energy and work done by the gas during the process 1-2?

a)

$\Delta U=0$ W by the gas > 0

b)

$\Delta U>0$ W by the gas = 0

c)

$\Delta U<0$ W by the gas < 0

d)

$\Delta U=0$ W by the gas = 0

24.

Which of the substances A, B or C has the highest specific heat? The temperature Vs heat graph is

a)

D

b)

B

c)

C

d)

A

25.

The change in internal energy by the system in going through cycle is

a)

$10^7\pi J$

b)

$10^{-3}J$

c)

0

d)

$10^2\pi J$

26.

If C_p = 34.4 J /mol K and value of R is 8.314 then

a)

C_v = 26.1 J/ mol K

b)

C_v = 20.1 J/ mol K

c)

C_v = 10.1 J/ mol K

d)

C_v = 120.1 J/ mol K

27.

The state of an ideal gas was changed three times at three different temperatures. The diagram represents three different isothermal curves. Which of the following is true about the temperature of the gas?

a)

T₁ > T₂ > T₃

b)

T₁ < T₂ < T₃

c)

T₁ > T₂ < T₃

d)

T₁ > T₂ = T₃

28.

The ratio of W_isothermal to W_adiobatic during same expansion is

a)

> 1

b)

=1

c)

<1

d)

Zero

29.

In the process A to B to C, 20J of heat is supplied from A to B. 20.5J of heat has been removed from B to C and 2J of heat has been added from C to A. Calculate the value of ‘V’ from the given conditions in the diagram. The values of pressure and volume given in the graph are in S.I. units.

a)

4m³

b)

1.5m³

c)

3m³

d)

8m³

30.

Find internal energy of system containing 2moles of oxygen and 1 mole of argon

a)

9 RT

b)

10 RT

c)

15 RT

d)

11 RT

31.

If 1 mole of mono atomic gas $\gamma$ = 5/3 is mixed with 1 mole of diatomic gas $\gamma$ = 7/5. What is the value of the $\gamma$ for the mixture.

a)

1

b)

1.5

c)

3.5

d)

2

32.

The specific heat of a gas in an isothermal process is

a)

Infinity

b)

Negative

c)

Zero

d)

Remain constant

33.

Which of the following parameters does not characterize the thermodynamic state of matter?

a)

Temperature

b)

Pressure

c)

Work

d)

Volume

34.

The area under a curve on P–V diagram represents

a)

The state of a system

b)

The work done on or by the system

c)

The work done in a cyclic process

d)

Internal energy of the system

35.

When the temperature of the gas system is changed by 30K and the internal energy of the system is changed by 48J, the molar specific heat of system at constant volume will be:

a)

0.6J/mol.K

b)

1.0J/mol.K

c)

1.6J/mol.K

d)

2.1J/mol.K

36.

During adiabatic compression of a gas, its temperature

a)

Remains constant

b)

Becomes zero

c)

Falls

d)

Rises

37.

As $C_P-C_v=R$ Shows that $C_p>C_v$ . What is also true?

a)

$\Delta T_p>\Delta T_v$

b)

$\Delta U_p>\Delta U_v$

c)

Both A and B

d)

$\Delta U_p=\Delta U_v$

38.

How much heat is absorbed by 100g of water when its temperature decreases from 25°C to 5°C?

a)

84,00 j

b)

–2000/4.2 j

c)

2000/4.2 j

d)

–84,00 j

39.

110 J of heat is added to a gaseous system, whose internal energy change is 40 J, then the amount of external work done is

a)

150 J

b)

70 J

c)

110 J

d)

40 J

40.

A thermo-dynamical system is changed from state (P₁,V₁ ) to (P₂ ,V₂ )

different process. The quantity which will remain same will be

a)

$\Delta Q$

b)

$\Delta W$

c)

$\Delta Q+\Delta W$

d)

$\Delta Q-\Delta W$

Physics Unit 5 Test

Total questions: 40

Worksheet time: 3600secs

Similar Resources on Wayground