MCQOPTIONS

Explore topic-wise MCQs in Thermal Engineering.

This section includes 15 Mcqs, each offering curated multiple-choice questions to sharpen your Thermal Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.	What is the efficiency of an ideal air standard otto cycle if the compression ratio is 7?
A.	51.5%
B.	54%
C.	52.1%
D.	50%
Answer» C. 52.1%

2.	What is the efficiency of an ideal air standard otto cycle if the clearance volume is 20% of the swept volume?
A.	52.1%
B.	50.1%
C.	55.1%
D.	51.1%
Answer» E.

3.	In an ideal otto cycle works between minimum and maximum temperature of 300K and 1800K. What is the compression ratio?
A.	4
B.	6
C.	8
D.	5
Answer» C. 8

4.	What is the efficiency of an ideal air standard otto cycle if the clearance volume is 10% of the swept volume?
A.	39.8%
B.	39.2%
C.	61.7%
D.	61.1%
Answer» D. 61.1%

5.	What is the efficiency of an ideal air standard otto cycle if the compression ratio is 8.5?
A.	67.5%
B.	57.5%
C.	48.5%
D.	47.5%
Answer» C. 48.5%

6.	For same compression ratio and heat supplied
A.	Otto cycle is more efficient
B.	Diesel cycle is more efficient
C.	Dual cycle is more efficient
D.	Both diesel and otto cycle are equally efficient
Answer» B. Diesel cycle is more efficient

7.	What is the value of working fluid in otto cycle?
A.	1.0
B.	1.2
C.	1.4
D.	1.8
Answer» D. 1.8

8.	The compression ratio (rk) of otto cycle is equal to __________
A.	r<sub>k</sub> = volume of the cylinder at the beginning of the compression/volume of the cylinder at the end of the compression
B.	r<sub>k</sub> = volume of the cylinder at the end of the compression/ volume of the cylinder at the beginning of the compression
C.	r<sub>k</sub> = clearance volume/ volume of the cylinder at the beginning of the compression
D.	r<sub>k</sub> = volume of the cylinder at the end of the compression/clearance volume
Answer» B. r<sub>k</sub> = volume of the cylinder at the end of the compression/ volume of the cylinder at the beginning of the compression

9.	How the efficiency of SI engine is affected by change in specific heat ratio of working fluid?
A.	The efficiency of SI engine increases with increase in specific heat ratio of working fluid
B.	The efficiency of SI engine decreases with increase in specific heat ratio of working fluid
C.	The efficiency of SI engine increases with decrease in specific heat ratio of working fluid
D.	The efficiency of SI engine does not affected by change in specific heat ratio of working fluid
Answer» B. The efficiency of SI engine decreases with increase in specific heat ratio of working fluid

10.	Which of the following is not a use of gasoline blend like gasoline mixed with tetraethyl lead in internal combustion engine?
A.	Increases the octane rating fuel
B.	Allows engine to operate at high compression ratio
C.	Avoid auto ignition of fuel
D.	Allows engine to operate at low compression ratio
Answer» E.

11.	In otto cycle heat rejection occurs at __________
A.	Reversible constant volume process
B.	Reversible constant pressure process
C.	Irreversible constant volume process
D.	Irreversible constant pressure process
Answer» B. Reversible constant pressure process

12.	Otto cycle is air standard cycle of _____________
A.	S.I. engine
B.	C.I. engine
C.	Both SI and CI engine
D.	Neither SI nor CI engine
Answer» B. C.I. engine

13.	An air standard otto cycle consist of ________
A.	One constant pressure process and three adiabatic process
B.	One constant pressure process, one constant volume process and two adiabatic process
C.	Two constant volume process and two adiabatic process
D.	Two constant pressure process and two adiabatic process
Answer» D. Two constant pressure process and two adiabatic process

14.	What is the efficiency of the otto cycle?
A.	1 ( frac{1}{r^{ -1}} )
B.	1 r<sup> -1</sup>
C.	r<sup> -1</sup>
D.	1 ( frac{1}{r^{ +1}} )
Answer» B. 1 r<sup> -1</sup>

15.	Which cycle is idealized cycle for the spark ignition internal combustion engines?
A.	Otto cycle
B.	Diesel cycle
C.	Dual cycle
D.	Bryton cycle
Answer» B. Diesel cycle