Deck 6: Thermodynamics and Gas Laws

Question 1

During a throttling process

A)exchange of heat doesnot take place
B)expandingsteam does nowork
C)internal energy of steamdoes not change
D)all of the above

Answer 1

all of the above

Question 2

Under which of the following conditions all gases behave ideally?

A)high pressure conditions
B)law pressure conditions
C)vaccum conditions
D)all of the aboveconditions

Answer 2

law pressure conditions

Question 3

……….. Is the unit of entropy

A)j/kg
B)j/kg k
C)j/k
D)j/kgs

Answer 3

j/kg k

Question 4

Internal energy & enthalpy of an ideal gas are functions of

A)pressure only
B)temperature only
C)specific volume only
D)temperature & pressure

Question 5

When two gases suddenly mix up with each other then resultant entropy of the system will

A)remain unaltered
B)decrease
C)increase
D)becomes zero

Question 6

On which of the following factors does air standard efficiency of a diesel cycle depend?

A)adiabatic compression ratio
B)ratio of specific heats
C)cut-off ratio
D)all of the above

Question 7

Regarding enthalpy which of the following statements is incorrect?

A)it is the function of specific heat at constantvolume
B)it is the extensive property of the system
C)it is the sum of internal energy & the pressurevolume product
D)it is the same as heat transfer during constantpressure process

Question 8

Which of the following processes is reversible process?

A)throttling
B)adiabatic
C)isothermal
D)none of the above

Question 9

Which of the following processes are reversible processes?

A)isothermal & adiabatic
B)constant volume &constant pressure
C)hyperbolic & pv= constant
D)none of the above

Question 10

For ……. The internal energy & enthalpy are the functions of temperature only

A)perfect gas
B)water in pipes surrounded by steam
C)saturated steam
D)superheated steam

Question 11

The index of compression n tends to reach ?(ratio of specific heats)

A)when process is isothermal
B)when process is isentropic
C)when process is isentropic & specific heat does not change with temperature
D)when flow is uniform & steady

Question 12

In the reversible polytropic process the value of exponent n varies between

A)0.2 to 1
B)1.0 to 1.2
C)1.2 to 1.4
D)1.4 to 2.0

Question 13

An ideal gas as compared to a real gas at very high pressure occupies

A)same volume
B)less volume
C)more volume
D)all of the above

Question 14

Adiabatic & isothermal processes are identical at

A)absolute zerotemperature
B)below 0°c temperature
C)saturation temperature
D)critical temperature

Question 15

In polytropic process pv=C the value of exponent n=±? is indicative of

A)isobaric process
B)isentropic process
C)isochoric process
D)throttling process

Question 16

Entropy in statistical thermodynamics is defined as

A)a universal property
B)reversible heat transfer
C)degree of randomness
D)measure of reversibilityof a system

Question 17

A mixture of gases expands from 0.03 m³ to 0.06 m³ at a constant pressure of 1 Mpa & absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is

A)30 kj
B)54 kj
C)84 kj
D)114 kj

Question 18

Increase in entropy of a system represents

A)increase in availability ofenergy
B)increase in temperature
C)decrease in pressure
D)degradation of energy

Question 19

Which one of the following pairs best expresses a relationship similar to that expressed in the pair 'pressure-volume' for a thermodynamic system undergoing a process?

A)enthalpy-entropy
B)pressure-enthalpy
C)pressure-temperature
D)temperature-entropy

Question 20

Variations of pressure & volume at constant temperature are correlated through

A)charle's law
B)boyle's law
C)gas law
D)gay lussac's law

Question 21

The relationship between pressure & volume is expressed as pv=const. Select wrong statement

A)expansion with n=0 is a constant pressure process
B)expansion with n=? is an adiabatic process
C)expansion with n=? is not possible
D)expansion at constant temperature has n=1

Question 22

A gas expands from initial condition of (p1, v1, T1) to final condition (p2, v1, T2), then according to Charle's law:

A)p1t1=p2t2
B)p1p2 = t1t2
C)p1+ t2 = p2 + t1
D)p1t2 = p2t1

Question 23

Air expands from initial condition of p1, v1 to final condition of 1/2 p1, 2v1. Choose the correct statement

A)no work is performed during expansion
B)expansion is isothermal
C)expansion is polytropic with n= 1.2
D)expansion is adiabatic

Question 24

Air with initial condition of p1, v1 expands to final condition of p1/2, 3v1. The process is

A)hyperbolic
B)adiabatic
C)polytropic with n > 1
D)polytropic with n < 1

Question 25

The internal energy of a perfect gas is a function of

A)pressure change &temperature
B)temperature change &specific heat
C)pressure & work supplied
D)temperature