Deck 18: Thermodynamics and Temperature Scales

Question 1

When pw is very small,

A)saturation temperature of water vapour at pw is less than atmospheric temperature
B)water vapour in air exists in superheated state
C)air is said to be in unsaturated state
D)all of the mentioned

Answer 1

all of the mentioned

Question 2

Relative humidity is defined as

A)(saturation pressure of pure water) / pw
B)pw / (saturation pressure of pure water)
C)(saturation pressure of pure water) / p
D)p / (saturation pressure of pure water)

Answer 2

pw / (saturation pressure of pure water)

Question 3

For saturated air, relative humidity is 0%.

Answer 3

False

Question 4

If water is injected into a container with has unsaturated air,

A)water will evaporate
B)moisture content of air will decrease
C)pw will decrease
D)all of the mentioned

Question 5

Humidity ratio is given by the ratio of

A)(mass of dry air per unit mass of water vapour)^2
B)1/(mass of dry air * mass of water vapour)
C)water vapour mass per unit mass of dry air
D)mass of dry air per unit mass of water vapour

Question 6

Which of the following statement is true?

A)dew point temperature is the temperature at which water vapour starts condensing
B)dry bulb temperature is recorded by thermometer with dry bulb
C)wet bulb temperature is recorded by thermometer when bulb is covered with a cotton wick which is saturated with water
D)all of the mentioned

Question 7

The wet bulb temperature is the   temperature recorded by moistened bulb.

A)lowest
B)highest
C)atmospheric
D)none of the mentioned

Question 8

Air can be cooled and dehumidified by

A)circulating chilled water in tube across air flow
B)placing evaporator coil across air flow
C)spraying chilled water to air
D)all of the mentioned

Question 9

When two equilibrium states are infinitesimally near,

A)dq/t=ds
B)dq/t>ds
C)dq/tD)none of the mentioned

Question 10

The greater the temperature, the___________is the vapour pressure.

A)lower
B)higher
C)depends on the substance
D)none of the mentioned

Question 11

It is necessary to have a temperature difference to obtain work of any cycle.

Question 12

The absolute thermodynamic temperature scale is also known as

A)celsius scale
B)kelvin scale
C)fahrenheit scale
D)none of the mentioned

Question 13

In defining the temperature scale, the standard reference point is taken as

A)zero kelvin
B)boiling point of water
C)triple point of water
D)none of the mentioned

Question 14

When the heat transferred isothermally between the given___________  decreases, the temperature___________

A)isotherms, increases
B)isotherms, decreases
C)adiabatics, increases
D)adiabatics, decreases

Question 15

If a system undergoes a reversible isothermal process without transfer of heat, the temperature at which this process takes place is called

A)absolute zero
B)triple point of water
C)boiling point of water
D)none of the mentioned

Question 16

A definite zero point___________on the absolute temperature scale but this point___________be reached___________violation of the second law.

A)doesnot, can, without
B)exists, cannot, without
C)exists, can, with
D)none of the mentioned

Question 17

Which law is stated here, "It is impossible to reduce any system to the absolute zero of temperature in a finite number of operations.

A)first law of thermodynamics
B)second law of thermodynamics
C)third law of thermodynamics
D)none of the mentioned

Question 18

The statement of third law is also called the Fowler-Guggenheim statement of the third law.

Question 19

The Kelvin temperature is numerically equal to the___________  and may be measured by means of a___________  

A)gas temperature, liquid thermometer
B)ideal gas temperature, gas thermometer
C)ideal gas temperature, liquid thermometer
D)none of the mentioned

Question 20

During a fluid flow, the temperature is developed due to                 

A)increase in density
B)change in pressure
C)translational kinetic energy
D)fluid level

Question 21

The equation for the average kinetic energy is                   

A)0.5 kt
B)1.5 kt
C)2.5 kt
D)3.5 kt

Question 22

Entropy occurs due to___________      

A)change in macroscopic variables
B)volumetric changes only
C)mass changes only
D)temperature only

Question 23

Efficiency of a heat engine is defined as

A)total heat output / net work input
B)total heat input / net work output
C)net work output / total heat input
D)net work input / total heat output

Question 24

A TER which transfers heat to system is called___________and one which receives heat is called___________

A)source, sink
B)sink, source
C)sink, sink
D)source, source

Question 25

A reversible cycle has following processes.

A)4 isothermal processes
B)4 adiabatic processes
C)2 isothermal and 2 adiabatic processes
D)none of the mentioned