Which of the following statement is correct?

Solution (By Examveda Team)

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