FBISE, NCP & NBF-aligned resources for Classes 9–12
Browse by Class
Browse by Type
Physics Chapter 8 : Topic 19
Entropy and Energy Degradation
1 / 30
An increase in entropy of a system indicates:
Reasoning: Higher entropy means energy becomes more dispersed and less available for doing useful work.
2 / 30
Energy degradation refers to:
Reasoning: Energy is not destroyed; it becomes less available for performing useful work.
3 / 30
The increase in entropy does not mean that:
Reasoning: The first law states that energy is conserved; entropy increase only represents energy degradation.
4 / 30
When heat flows from a hot object to a cold object, entropy:
Reasoning: Heat transfer causes energy distribution over a larger region, increasing entropy.
5 / 30
The second law of thermodynamics explains that:
Reasoning: During real processes, some energy becomes unavailable for useful work.
6 / 30
A high entropy system has:
Reasoning: Greater entropy means energy is more randomly distributed and less convertible into work.
7 / 30
Which form of energy is generally more useful for doing work?
Reasoning: Organized energy forms can be converted into useful work more easily.
8 / 30
During friction, mechanical energy is converted into heat. This process:
Reasoning: Friction spreads energy as random molecular motion, increasing entropy.
9 / 30
The degradation of energy means:
Reasoning: Energy remains conserved but becomes less organized.
10 / 30
In a natural irreversible process:
Reasoning: Irreversible processes increase entropy and reduce energy quality.
11 / 30
A hot cup of tea cooling in a room demonstrates:
Reasoning: Heat spreads into surroundings, increasing entropy and reducing useful energy.
12 / 30
Heat energy at a high temperature is more useful because:
Reasoning: A larger temperature difference allows more conversion into useful work.
13 / 30
When two bodies at different temperatures reach thermal equilibrium:
Reasoning: Energy becomes evenly distributed, reducing the ability to perform work.
14 / 30
A heat engine cannot convert all heat into work because:
Reasoning: The second law requires some heat rejection, causing energy degradation.
15 / 30
Waste heat from a machine represents:
Reasoning: Waste heat is dispersed energy that cannot be completely converted into work.
16 / 30
Burning fuel increases entropy because:
Reasoning: Combustion converts concentrated chemical energy into dispersed thermal energy.
17 / 30
Which process shows degradation of energy?
Reasoning: Friction converts useful mechanical energy into less useful thermal energy.
18 / 30
Electrical energy in a heater is degraded because:
Reasoning: Electrical energy becomes random molecular motion, increasing entropy.
19 / 30
Which process has the greatest energy degradation?
Reasoning: Irreversible processes generate entropy and degrade energy.
20 / 30
An increase in entropy means:
Reasoning: Entropy measures the spreading and randomness of energy.
21 / 30
Why can a car engine not convert all fuel energy into motion?
Reasoning: The second law limits conversion efficiency due to entropy increase.
22 / 30
A reversible process is ideal because:
Reasoning: A reversible process has no entropy generation.
23 / 30
The entropy of the universe increases because:
Reasoning: Irreversible processes cause entropy increase in the universe.
24 / 30
A decrease in energy quality means:
Reasoning: Energy quantity is conserved, but quality decreases due to entropy increase.
25 / 30
Which statement correctly explains entropy increase?
Reasoning: Greater energy spreading increases disorder and entropy.
26 / 30
A machine receives $\mathbf{1000\ J}$ energy and produces $\mathbf{700\ J}$ useful work. The remaining energy is mainly:
Reasoning: The remaining $\mathbf{30}\mathbf{0\ J}$ is converted into less useful forms, mainly heat.
27 / 30
If entropy of a system increases, the available energy for useful work:
Reasoning: Higher entropy means less energy is available for organized work.
28 / 30
The ultimate result of increasing entropy in the universe is:
Reasoning: Entropy increase represents spreading of energy throughout the universe.
29 / 30
Which statement is correct about energy degradation?
Reasoning: The second law explains why energy quality decreases during real processes.
30 / 30
The best explanation of “increase in entropy means degradation of energy” is:
Reasoning: Entropy increase indicates that energy has become more dispersed and less useful.
Your score is
Restart quiz
