HSSC-1 (Class-11) Solved Physics MCQs; Unit-10: Thermodynamics;  (New Book/KPK Text Board, Peshawar) With Verified Answers 


1. Assume we can change the equilibrium state of a system via two different processes. Assume that the initial and the final state are the same. Which of the quantities ΔU, ΔQ, ΔW, and ΔT must be the same for the two processes?




... Answer is B. Only ΔU and ΔT
--------------------------


2. In any process the maximum amount of mechanical energy that can be converted to heat




... Answer is A. Depends upon the amount of friction
----------------------


3. In an isothermal change, internal energy




... Answer is D. remains constant
---------------------------


4. A thermos bottle containing hot coffee is vigorously shaken. Consider coffee as system, then its temperature




... Answer is A. Increases
-----------------------


5. Maximum work can be obtained in tie process called




... Answer is C. Isothermal
----------------------------


6. A heat engine takes in 800 J of heat at 1000 K and exhausts 600 J of heat at 400 K. What the actual efficiency of this engine?




... Answer is A. 25%
Efficiency η% = 1 -   x 100 = 1 - \ frac {600}{800}= 25%


7. If the temperature of the heat source is increased, the efficiency of a Carnot's engine :




... Answer is A. Increases
-------------------------


8. Triple point of water is




... Answer is D. 273.16°K
--------------------------------


9. A real gas can be approximated to an ideal gas at




... Answer is A. Low density
------------------------


10. If the volume of the gas is to be increased by 4 times, then




... Answer is C. At constant T the pressure must be increased by four times
------------------------


11. In which of the systems listed below is the entropy decreasing?




... Answer is A. A gas is cooled.
-------------------------


12. If the temperature of the source and sink of a Carnot engine having efficiency η are each decreased by 100K, then the efficiency η :




... Answer is C. increases.
Let T1 = 200 K and T2 = 400 K 👉 Efficiency η% = 1 - \ frac {T2}{T1} x 100 = 1 - \ frac {200 K}{400 K}= 50% 👉 When the temperature is decrease by 100 K 👉 Efficiency η% = 1 - \ frac {T2 - 100 K}{T1 - 100 K} x 100 = 1 - \ frac {200 K - 100 K}{400 K - 100 K}= 67%




Try the Above MCQs as a Quiz ( Click Here to Play the Quiz )

************************************

Shortcut Links For 


1. Website for School and College Level Physics   
2. Website for School and College Level Mathematics  
3. Website for Single National Curriculum Pakistan - All Subjects Notes 

© 2022-Onwards by Academic Skills and Knowledge (ASK)     

Note:  Write to me in the comment box below for any query and also Share this information with your class-fellows and friends.