1. What is caking in Power Plants?
a) making cakes of coal out of fine powders
b) a variety of free burning coals
c) coal produced from burning of wood in inert atmosphere
d) in boiler furnace some coals become plastic and form lumps or masses of coal
Explanation: When many bituminous coals are heated, they soften and form a plastic mass that swells and re solidifies into a porous solid
2. Water gas is a mixture of ___________
a) CO2 and O2
b) O2 and H2
c) H2, N2 and O2
d) CO, N2 and H2
Explanation: Water gas is basically HHO that is H2 and O2.
3. Critical pressure of water is ___________
a) 1 kg / cm2
b) 100 kg / cm2
c) 155 kg / cm2
d) 217.7 kg / cm2
Explanation: The critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature.
4. Coal used in power plant is also known as ___________
a) steam coal
b) charcoal
c) coke
d) soft coal
Explanation: Because this coal is used to generate steam.
5. The temperature to which air must be cooled in order to become saturated is the ___________
a) minimum temperature
b) dew point temperature
c) wet-bulb temperature
d) freezing point
Explanation: The dew point is the temperature at which the water vapour in air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates.
6. The cycle efficiency ________________ with the _____________ of condenser pressure.
a) decreases, decrease
b) increases, decrease
c) remains same, decrease
d) does not vary, decrease
Explanation: As the decrease in condenser pressure mainly depends on the available cooling water temperature & thus on the climatic conditions of the place. Hence, cycle efficiency being a function of condenser pressure has an inverse relation with the condenser pressure.
7. What is the relation between cooling water temperature (tc1) & condenser pressure (pc)?
a) tc1 is directly proportional to pc
b) tc1 is directly proportional to 2xpc
c) tc1 is directly proportional to 5xpc
d) tc1 is directly proportional to 6xpc
Explanation: Cooling water temperature is directly proportional to condenser pressure 1xpc
8.An increase in inlet steam temperature ___________ the heat rate.
a) lowers
b) increases
c) does not have any effect on
d) temperature has no significance in heat rate
Explanation: An increase in inlet steam temperature, i.e. an increase in superheat at constant inlet steam pressure & condenser pressure gives a steady improvement in cycle efficiency & lowers the heat rate due to an increase in the mean temperature of heat addition
9. What is the effect of increasing superheat at constant inlet steam pressure & condenser pressure on cycle efficiency?
a) Steady decrement in cycle efficiency
b) Steady improvement in cycle efficiency
c) No effect on cycle efficiency
d) None of the mentioned
Explanation: An increase in inlet steam temperature, i.e. an increase in superheat at constant inlet steam pressure & condenser pressure gives a steady improvement in cycle efficiency & lowers the heat rate due to an increase in the mean temperature of heat addition.
10. What is the effect of increasing superheat at constant inlet steam pressure & condenser pressure on mean temperature of heat addition?
a) increases
b) decreases
c) remains same
d) none of the mentioned
Explanation: An increase in inlet steam temperature, i.e. an increase in superheat at constant inlet steam pressure & condenser pressure gives a steady improvement in cycle efficiency & lowers the heat rate due to an increase in the mean temperature of heat addition.