Deck 5: Gas Laws and Thermodynamics

Question 1

The amount of heat absorbed by a system at lower temperature is

A)coeff. of performance
B)efficiency
C)work supplied
D)refrigerating effect

Answer 1

work supplied

Question 2

In an ideal gas the partial pressure of a component is

A)inversely proportional to the square of the molefraction
B)directly proportional to the mole fraction
C)inversely proportional to the mole fraction
D)equal to the mole fraction

Answer 2

directly proportional to the mole fraction

Question 3

The value of the univesal gas constant is

A)0.314 j/kg k
B)83.14 kj/kg k
C)848 kj/kg k
D)8.314 kj/kg k

Answer 3

8.314 kj/kg k

Question 4

Choose the correct answer

A)a perfect gas does not obey the law pv=rt
B)a perfect gas obeys the law pv=rt & has constant specific heat
C)a perfect gas obeys the law pv=rt but have variable specific heat capacities
D)all of the above

Question 5

Boyle's law states that, when tempearture is constant, the volume of a given mass of a perfect gas

A)varies directly as the absolute pressure
B)varies inversely as the absolute pressure
C)varies as square of the absolute pressue
D)does not vary with the absolute pressure

Question 6

Charle's law states that if any gas is heated at constant pressure, its volume

A)changes directly as it absolute temperature
B)changes inversely as its absolute temperature
C)changes as square of the absolute temperature
D)does not change with absolute temperature

Question 7

The equation of state of an ideal gas is a relationship between the variables:

A)pressure & volume
B)pressure & temperature
C)pressure, volume & temperature
D)none of the above

Question 8

Joule's law states that the specific internal energy of a gas depends only on

A)the pressure of the gas
B)the volume of the gas
C)the temperature of the gas
D)none of the above

Question 9

The change of entropy is considered to be ……… when heat is absorbed by the gas

A)positive
B)negative
C)zero
D)none of the above

Question 10

………. Is one in which neither any heat enters nor leaves the system

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

Question 11

Entropy of the universe

A)tends to zero
B)tends to a minimum
C)tends to a maximum
D)none of the above

Question 12

A gas can never be liquid

A)above criticaltemperature
B)when it is diatomic
C)when it is impure
D)above roomtemperature

Question 13

Which of the following remains constant during an adiabatic expansion

A)entropy
B)temperature
C)internal energy
D)none of the above

Question 14

In which of the following processes the change in internal energy of a gas is equal to the work done

A)adiabatic process
B)isothermal process
C)constant volume process
D)constant pressure process

Question 15

The specific heat of a gas is a function of

A)temperature only
B)temperature & pressure
C)temperature & entropy
D)temperature, pressure& entropy

Question 16

In a Carnot cycle which of the following processez must be carried out at extremely slow speed?

A)isothermal compression
B)adiabatic expansion
C)adiabatic compression
D)none of the above

Question 17

In the case of real gases, cp will be equal to cv

A)at absolute zero
B)at triple point
C)at critical temperature
D)above criticaltempeature

Question 18

The physical properties of a perfect gas are controlled by which of the following variables?

A)volume
B)temperature
C)pressure
D)all of the above

Question 19

Universal gas constant is defined as equal to the product of the molecular weight of the gas &

A)gas constant
B)specific heat at constant volume
C)specific heat a constant pressure
D)ratio of two specific heats

Question 20

All engineering process, strictly speaking are

A)reversible cycle
B)irreversible
C)quasti-static
D)thermodynamically inequillibrium

Question 21

Isothermal, isobaric, isochoric & adiabatic processes, under ideal conditions, are …. Processes

A)thermodynamic
B)stable
C)dynamic
D)quasi-static

Question 22

Change of entropy depends upon which of the following?

A)change of heat
B)change of specific heats
C)change of pressure &volume
D)none of the above

Question 23

In a reversible adiabatic process head added is equal to

A)zero
B)positive value