Engineering Questions with Answers - Multiple Choice Questions
Thermal Engineering MCQ’s – Reciprocating Steam Engine – Theoretical Indicator Diagram
1 - Question
An indicator diagram shows _____
a) The variation of temperature of the steam and its pressure during the cycle of operations
b) The variations of temperature and volume of steam during the cycle of operation
c) The variations of steam pressure and its volume in the cylinder during the cycle of operations
d) The variation of temperature of steam and its specific volume during the cycle of operations
View Answer
Explanation: The plot of the variations of steam pressure and volume in the cylinder during the cycle of operations is called an indicator diagram. Indicator diagrams useful in estimating the performance of a reciprocating steam engine.
2 - Question
In a theoretical or hypothetical indicator diagram the expansion is assumed to be _____
a) Parabolic
b) Linear
c) Exponential
d) Hyperbolic
View Answer
Explanation: Theoretical or hypothetical indicator diagram is based on some assumptions. One of these assumptions is that the expansion process is hyperbolic. Mathematically, the following relationship holds true between pressure (P) and volume (V) – PV = Constant.
3 - Question
In the given indicator diagram, Point 1 is called _____
a) Point of cut-off
b) Point of release
c) Point of flow
d) Point of admission
View Answer
Explanation: At point 1 steam supply is cutoff and hence is called the point of cut-off. The point 5 is called the point of admission and the point 2 is called the point of release. During the process point 5 to point 1 steam is admitted inside the engine cylinder.
4 - Question
Which of the following processes is the expansion process? (Refer to the given image)
a) Process 5 to 1
b) Process 1 to 2
c) Process 2 to 3
d) Process 3 to 4
View Answer
Explanation: Process 1 to 2 represents the expansion process. The process is hyperbolic. During the expansion process the steam expands in the engine cylinder to the end of the stroke. Point 1 and 2 are called point of cut-off and point of release respectively.
5 - Question
With reference to the given image, steam is admitted in the engine cylinder at _____
a) Point 5
b) Point 1
c) Point 2
d) Point 3
View Answer
Explanation: At point 5 steam is admitted in the engine cylinder. The steam admitted has same pressure as the boilers. Point 5 is also called as point of admission. The expansion of steam starts at point 1.