Questions set 54

Heat Engines

1.      A heat engine converts heat energy from fuel combustion or any other source into which type of work
a) Electrical work
b) Mechanical work
c) Pressure work
d) None of the mentioned
Answer: b
Explanation: A heat engine gives mechanical work as output.

2.      A steam engine comes under the category of
a) External combustion engines
b) Internal combustion engines
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: A steam engine is a External combustion engine

3.      Which of these is a power absorbing heat engine
a) Steam engine
b) Petrol engine
c) Air compressor
d) None of the mentioned
Answer: c
Explanation: An air compressor is a power absorbing heat engine.

4.      Which of these is a type of reciprocating steam engine
a) Simple
b) Compound
c) Uniflow
d) All of the mentioned
Answer: d
Explanation: Simple, compound and uniflow are types of reciprocating steam engine.

5.      A gas undergoes step 2 in Carnot cycle. Which of these processes describes the 2nd step
a) Isentropic expansion
b) Isentropic compression
c) Isothermal expansion
d) Isothermal compression
Answer: a
Explanation: The 2nd process in carnot cycle is isentropic expansion.

6.      A gas undergoes step 4 in Carnot cycle. Which of these processes describes the 2nd step
a) Isentropic expansion
b) Isentropic compression
c) Isothermal expansion
d) Isothermal compression
Answer: b
Explanation: The 4th process in carnot cycle is isentropic compression.

7.      A gas undergoes isothermal compression in Carnot cycle. Which step does it undergo
a) 1st
b) 2nd
c) 3rd
d) 4th
Answer: c
Explanation: Isothermal compression is the 3rd step in Carnot cycle.

8.      Thermal power plants operate on which of these cycles
a) Otto cycle
b) Rankine cycle
c) Carnot cycle
d) Stirling cycle
Answer: b
Explanation: Thermal power plants operate on Rankine cycle.

9.      The efficiency of a combined cycle gas turbine(steam cooled) can range as high as
a) 20%
b) 30%
c) 40%
d) 60%
Answer: d
Explanation: A steam cooled combined cycle gas turbine can have efficiency as high as 60%.

10.  One ‘ton of refrigeration’ equals how much Btu/hr.
a) 14,500 Btu/hr
b) 12,000 Btu/hr
c) 13,000 Btu/hr
d) 15,000 Btu/hr
Answer: b
Explanation: One ton of refrigeration equals 12,000 Btu/hr.