Explore topic-wise MCQs in Thermodynamics.

This section includes 43 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.

1.

Heat rate indicates?

A. heat added per unit volume
B. heat added per unit of work produced
C. heat added per unit of mass stored
D. heat added per unit area
Answer» C. heat added per unit of mass stored
Discussion
2.

Heat rejection in a condenser is to?

A. cooled water
B. coolant
C. cooling water
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
3.

What approximate percentage of energy in the fuel is converted to electricity?

A. 55%
B. 45%
C. 35%
D. 25%
Answer» D. 25%
Discussion
4.

Which of these shows the formula for the efficiencies of the auxiliaries n1?

A. n1 = (net power transmitted by the generator x gross power produced by the plant)
B. n1 = (net power transmitted by the generator / gross power input to the plant)
C. n1 = (net power transmitted by the generator / gross power produced by the plant)
D. n1 = (net power transmitted by the generator / gross power transferred by the plant)
Answer» D. n1 = (net power transmitted by the generator / gross power transferred by the plant)
Discussion
5.

If Q1 represents the rate of heat addition to the cycle and Wnet represents net cycle work output, the expression for net cycle heat rate is?

A. Q1 + Wnet
B. Q1 / Wnet
C. Q1 / (1/Wnet)
D. Q1 x Wnet
Answer» C. Q1 / (1/Wnet)
Discussion
6.

The mechanical efficiency of a turbine is given by? (ntm denotes the mechanical efficiency)

A. ntm = (brake output of the turbine x internal output of the turbine)
B. ntm = (internal output of the turbine / break output of the turbine)
C. ntm = (brake output of the turbine / internal output of the turbine)
D. ntm = (brake output of the turbine – internal output of the turbin
E. ntm = (internal output of the turbine / break output of the turbine)c) ntm = (brake output of the turbine / internal output of the turbine)d) ntm = (brake output of the turbine – internal output of the turbine)
Answer» D. ntm = (brake output of the turbine – internal output of the turbin
Discussion
7.

Which of the following shows the correct relation? (nboiler denotes efficiency of a boiler)

A. nboiler = (rate of energy absorption by water to form steam / rate of energy released by the combustion of fuel)
B. nboiler = (rate of energy absorption by water to form steam + rate of energy released by the combustion of fuel)
C. nboiler = (rate of energy absorption by water to form steam – rate of energy released by the combustion of fuel)
D. nboiler = (rate of energy absorption by water to form steam x rate of energy released by the combustion of fuel)
Answer» B. nboiler = (rate of energy absorption by water to form steam + rate of energy released by the combustion of fuel)
Discussion
8.

The overall efficiency noverall of a steam power plant is given by?

A. noverall = (power available at the generator terminals / (Fuel burning rate x Calorific Value of the fuel))
B. noverall = (power available at the generator terminals + (Fuel burning rate x Calorific Value of the fuel))
C. noverall = (power available at the generator terminals – (Fuel burning rate x Calorific Value of the fuel))
D. none of the mentioned
Answer» B. noverall = (power available at the generator terminals + (Fuel burning rate x Calorific Value of the fuel))
Discussion
9.

The steam power plant is a bulk energy converter where fuel energy is converted to?

A. heat energy
B. electrical energy
C. chemical energy
D. none of the mentioned
Answer» C. chemical energy
Discussion
10.

Compressing steam in vapour form requires less work than compressing it in liquid form for same pressure rise.

A. true
B. false
Answer» C.
Discussion
11.

The efficiency of boiler is given by

A. energy supplied / energy utilized
B. energy utilized / energy supplied
C. heat supplied / energy utilized
D. none of the mentioned
Answer» C. heat supplied / energy utilized
Discussion
12.

The brake efficiency is given by

A. brake output / internal output
B. internal output / brake output
C. brake output / heat supplied
D. brake output / ideal output
Answer» E.
Discussion
13.

COMPRESSING_STEAM_IN_VAPOUR_FORM_REQUIRES_LESS_WORK_THAN_COMPRESSING_IT_IN_LIQUID_FORM_FOR_SAME_PRESSURE_RISE.?$

A. true
B. false
Answer» C.
Discussion
14.

EFFICIENCY_OF_A_POWER_PLANT_IS_MORE_IN_SUMMERS_OR_WINTERS??$

A. summers
B. winters
C. same in both
D. depends on variation
Answer» C. same in both
Discussion
15.

WHICH_OF_THESE_SHOWS_THE_FORMULA_FOR_THE_EFFICIENCIES_OF_THE_AUXILIARIES_N1??$

A. n<sub>1</sub> = (net power transmitted by the generator x gross power produced by the plant)
B. n<sub>1</sub> = (net power transmitted by the generator / gross power input to the plant)
C. n<sub>1</sub> = (net power transmitted by the generator / gross power produced by the plant)
D. n<sub>1</sub> = (net power transmitted by the generator / gross power transferred by the plant)
Answer» D. n<sub>1</sub> = (net power transmitted by the generator / gross power transferred by the plant)
Discussion
16.

Heat rejection in a condenser is to?$

A. cooled water
B. coolant
C. cooling water
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
17.

What_is_the_mechanical_efficiency_of_turbine?$

A. brake output / internal output
B. internal output / brake output
C. blade energy / energy supplied
D. none of the mentioned
Answer» C. blade energy / energy supplied
Discussion
18.

What_approximate_percentage_of_energy_in_the_fuel_is_converted_to_electricity?$

A. 55%
B. 45%
C. 35%
D. 25%
Answer» D. 25%
Discussion
19.

The relation between heat rate & efficiency is?

A. both are directly proportional
B. both are inversely proportional
C. they are independent of each other
D. heat rate is also called efficiency
Answer» C. they are independent of each other
Discussion
20.

Gross cycle heat rate is equal to?

A. (rate of heat addition / turbine output)
B. (rate of heat rejection / turbine input)
C. (heat rejected / turbine output)
D. none of the mentioned
Answer» B. (rate of heat rejection / turbine input)
Discussion
21.

Which of the following parameters affects the fuel economy?

A. heat constant
B. specific heat
C. heat rate
D. heat consumption
Answer» D. heat consumption
Discussion
22.

Heat_rate_indicates?

A. heat added per unit volume
B. heat added per unit of work produced
C. heat added per unit of mass stored
D. heat added per unit area
Answer» C. heat added per unit of mass stored
Discussion
23.

The efficiency of boiler is given b?

A. energy supplied / energy utilized
B. energy utilized / energy supplied
C. heat supplied / energy utilized
D. none of the mentioned
Answer» C. heat supplied / energy utilized
Discussion
24.

Name the major isotope present in steam generated in a Boiling Water Reactor?

A. N-16
B. D-32
C. N-32
D. D-16
Answer» B. D-32
Discussion
25.

Which of these is not an auxiliary equipment in a power plant?

A. Fans
B. Crushers
C. Galvanisers
D. Conveyors
Answer» D. Conveyors
Discussion
26.

Which of the following efficiency is true?

A. internal efficiency takes internal losses into consideration
B. mechanical efficiency only considers the external losses
C. brake efficiency considers both internal and external losses
D. all of the mentioned
Answer» E.
Discussion
27.

What includes fixed cost?

A. cost of land, Cost of building, Cost of equipment, Cost of installation
B. interest
C. management cost
D. all of the mentioned
Answer» E.
Discussion
28.

The generator efficiency n of the electric alternator is?

A. n = (electrical output at generator terminals / Brake output of the turbine)
B. n = (electrical output at generator terminals x Brake output of the turbine)
C. n = (electrical output at generator terminals / (1/ Brake output of the turbine))
D. none of the mentioned
Answer» B. n = (electrical output at generator terminals x Brake output of the turbine)
Discussion
29.

Under certain conditions, the specific enthalpies of dry steam, saturated water and wet steam are 2783 kJ/kg, 1219 kJ/kg and 2750 kJ/kg respectively. Determine the dryness fraction of wet steam.

A. 0.01
B. 0.02
C. 0.021
D. 0.03
Answer» D. 0.03
Discussion
30.

If Q1 represents the rate of heat addition to the cycle and W represents net cycle work output, the expression for net cycle heat rate is ?

A. Q<sub>1</sub> + W
B. Q<sub>1</sub> / W
C. Q<sub>1</sub> / (1/ W)
D. Q<sub>1</sub> x W
Answer» C. Q<sub>1</sub> / (1/ W)
Discussion
31.

The mechanical efficiency is given by

A. brake output / ideal output
B. brake output / internal output
C. brake output / heat supplied
D. internal output / brake output
Answer» C. brake output / heat supplied
Discussion
32.

The steam from steam generator of a nuclear power plant is best described as

A. superheated steam
B. supercritical steam
C. saturated dry steam
D. saturated wet steam
Answer» E.
Discussion
33.

The mechanical efficiency of a turbine is given by? (ntm denotes the mechanical efficiency)

A. n<sub>tm</sub> = (brake output of the turbine x internal output of the turbine)
B. n<sub>tm</sub> = (internal output of the turbine / break output of the turbine)
C. n<sub>tm</sub> = (brake output of the turbine / internal output of the turbine)
D. n<sub>tm</sub> = (brake output of the turbine – internal output of the turbine)
Answer» D. n<sub>tm</sub> = (brake output of the turbine ‚Äö√Ñ√∂‚àö√ë‚àö¬® internal output of the turbine)
Discussion
34.

Overall efficiency is the ratio of power available at generator terminals to rate of energy released by combustion of fuel.

A. true
B. false
C. can’t say
D. not true for all conditions
Answer» B. false
Discussion
35.

Which of the following shows the correct relation? (nboiler denotes efficiency of a boiler)

A. n<sub>boiler</sub> = (rate of energy absorption by water to form steam / rate of energy released by the combustion of fuel)
B. n<sub>boiler</sub> = (rate of energy absorption by water to form steam + rate of energy released by the combustion of fuel)
C. n<sub>boiler</sub> = (rate of energy absorption by water to form steam – rate of energy released by the combustion of fuel)
D. n<sub>boiler</sub> = (rate of energy absorption by water to form steam x rate of energy released by the combustion of fuel)
Answer» B. n<sub>boiler</sub> = (rate of energy absorption by water to form steam + rate of energy released by the combustion of fuel)
Discussion
36.

The generator efficiency is given by brake output / output at generator terminals.

A. true
B. false
Answer» C.
Discussion
37.

The lower is the value of heat rate, __________ is the efficiency.

A. lower
B. higher
C. same
D. depends on further parameters
Answer» C. same
Discussion
38.

The overall efficiency noverall of a steam power plant is given by?

A. n<sub>overall</sub> = (power available at the generator terminals / (Fuel burning rate x Calorific Value of the fuel))
B. n<sub>overall</sub> = (power available at the generator terminals + (Fuel burning rate x Calorific Value of the fuel))
C. n<sub>overall</sub> = (power available at the generator terminals – (Fuel burning rate x Calorific Value of the fuel))
D. none of the mentioned
Answer» B. n<sub>overall</sub> = (power available at the generator terminals + (Fuel burning rate x Calorific Value of the fuel))
Discussion
39.

The internal efficiency is given by

A. internal output / ideal output
B. ideal output / internal output
C. internal output / heat supplied
D. none of the mentioned
Answer» B. ideal output / internal output
Discussion
40.

Maximum energy of a power plant is lost in?

A. condensor
B. pump
C. boiler
D. environment
Answer» B. pump
Discussion
41.

Rate of energy released by the combustion of the fuel is given by?

A. Fuel burning rate x Calorific Value of the fuel
B. Fuel burning rate / Calorific Value of the fuel
C. Fuel burning rate + Calorific Value of the fuel
D. Fuel burning rate – Calorific Value of the fuel
Answer» B. Fuel burning rate / Calorific Value of the fuel
Discussion
42.

The work done in irreversible adiabatic expansion by the turbine is called

A. external work
B. internal work
C. zero work
D. useful work
Answer» C. zero work
Discussion
43.

The maximum work output that can be obtained per unit mass of steam is

A. reversible and isobaric enthalpy drop in turbine
B. reversible and isochoric enthalpy drop in turbine
C. reversible and adiabatic enthalpy drop in turbine
D. all of the mentioned
Answer» D. all of the mentioned
Discussion