ExamVeda
Login
Home
21
For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order
Discuss
Answer & Solution
Answer: Option A
No explanation is given for this question. Let's Discuss on Board
22
The __________ states that change of internal energy of a perfect gas is directly proportional to the change of temperature.
Discuss
Answer & Solution
Answer: Option D
No explanation is given for this question. Let's Discuss on Board
23
Select the wrong statement
Discuss
Answer & Solution
Answer: Option A
No explanation is given for this question. Let's Discuss on Board
24
The change of entropy, when heat is absorbed by the gas, is
Discuss
Answer & Solution
Answer: Option A
No explanation is given for this question. Let's Discuss on Board
25
When gas is heated at constant pressure, the heat supplied is utilized in
Discuss
Answer & Solution
Answer: Option C
No explanation is given for this question. Let's Discuss on Board
26
Superheated vapour behaves
Discuss
Answer & Solution
Answer: Option D
No explanation is given for this question. Let's Discuss on Board
27
Which of the following statement is correct?
Discuss
Answer & Solution
Answer: Option D
No explanation is given for this question. Let's Discuss on Board
28
Which of the following statement is correct?
Discuss
Answer & Solution
Answer: Option D
Solution:
Option A: The increase in entropy is obtained from a given quantity of heat at a low temperature.
This is TRUE.
Entropy change (ΔS) is defined as ΔS = Q/T, where Q is the heat added and T is the absolute temperature.
So, for the SAME amount of heat (Q), if the temperature (T) is lower, the entropy change (ΔS) will be greater. Think of it like this: adding a little heat to something already cold makes a bigger difference in its randomness than adding that same heat to something already hot.

Option B: The change in entropy may be regarded as a measure of the rate of the availability or unavailability of heat for transformation into work.
This is also TRUE.
Entropy is a measure of disorder or randomness in a system.
When entropy increases, the energy becomes less available to do work.
A higher entropy change means more energy has become unavailable for conversion into useful work.
It represents the degradation of energy.

Option C: The entropy represents the maximum amount of work obtainable per degree drop in temperature.
This is also TRUE in specific cases.
While not a general definition, it relates to how energy gets ‘lost’ to randomness as temperature changes.
The concept is more closely tied to exergy or availability, but entropy change is fundamentally related to the limit on how much work can be extracted from a system as it cools.
Since all three statements (A, B, and C) are correct, the answer is:
Option D: All of the above
29
The heat flows from a cold body to a hot body with the aid of an external source. This statement is given by
Discuss
Answer & Solution
Answer: Option C
No explanation is given for this question. Let's Discuss on Board
30
Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as
Discuss
Answer & Solution
Answer: Option B
No explanation is given for this question. Let's Discuss on Board