1. The humidity is represented in
a) Humidity chart
b) Psychometric chart
c) Psychometric chart or humidity chart
d) All of the mentioned
Explanation: The chart where dry bulb and wet bulb temperature are interlinked is a humidity chart or psychometric chart.
2. De-humidification is done in
a) Adiabatic temperature
b) Adiabatic saturated temperature
c) Adiabatic unsaturated temperature
d) None of the mentioned
Explanation: For de-humidification, there should be no heat addition or heat removal. For that, the adiabatic saturation temperature is maintained.
3. Partial pressure equals vapour pressure if it is__________
a) Saturated
b) Unsaturated
c) Isothermal
d) None of the mentioned
Explanation: At saturation, the vapour-gas mixture will be at equilibrium so the vapour pressure equals partial pressure.
4. Say True or False
I) Vapour- at superheated temperature
II) Gas – at condensation temperature
a) true
b) false
Explanation: Since vapour has liquid portion we cannot say superheated. Superheated means free from other components like unique gas.
5. Guess the saturated molar absolute humidity of the gas(A.- Vapour(B. mixture at 100 degree Celsius. Vapour pressure of A is 300 mmHg and the total pressure is 760 mmHg.
a) 0.39
b) 0.65
c) 0.60
d) Cannot determine
Explanation: Saturated molar humidity= Vapour pressure of A/ Vapour pressure of B
= 300/(760-300) =0.65.
6. The system is unsaturated if partial pressure _________ equilibrium vapour pressure.
a) Less than
b) Greater than
c) Equals to
d) All of the mentioned
Explanation: If saturated, the vapour pressure equals partial pressure. If unsaturated, the pressure will be less than vapour pressure.
7. Consider a saturated gas(A.-vapour(B. mixture , if the absolute molal humidity is 0.265 and the total pressure= 760 mmHg. Find the vapour pressure of B.
a) 149.21 mmHg
b) 159.21 mmHg
c) 169.21 mmHg
d) 600.8 mmHg
Explanation: First, we have to find the vapour pressure of A.
0.265= pA/760-pA
pA= 159.21
pB=760-159.21= 600.8.
8. The vapour pressure of the nitrogen gas is 400mmHg and the partial pressure is 300mmHg. Find the relative saturation.
a) 75
b) 133
c) 100
d) 50
Explanation: Relative saturation or relative humidity = (partial pressure/vapour pressure. x100
=75.
9. Thermometer measurement temperature is
a) Dry bulb temperature
b) Wet bulb temperature
c) Dew point temperature
d) Room temperature
Explanation: Dry bulb temperature is the actual measuring temperature of the thermometer.
10. Temperature at which the partial pressure of the gas-vapour mixture equals vapour pressure _______
a) Dry bulb temperature
b) Wet bulb temperature
c) Dew point temperature
d) None of the mentioned
Explanation: At saturation, the vapour pressure equals partial pressure. At dew point, saturation attains.