Heat Pump And Energy Transfer
A heat pump uses 200 J of work to deliver a total of 800 J of heat into a warm room during each operating cycle, so how much heat does it extract from the cold outside air?
Select the correct option:
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More thermodynamics Practice Questions
A gas is taken around a complete thermodynamic cycle and returns to its original state after several...
A gas is taken around a complete thermodynamic cycle and returns to its original state after several...
When 2 moles of a monatomic ideal gas are heated at constant pressure causing a temperature rise of ...
When 2 moles of a monatomic ideal gas are heated at constant pressure causing a temperature rise of ...
A balloon suddenly bursts and the compressed gas inside rushes out into the open atmosphere very rap...
A balloon suddenly bursts and the compressed gas inside rushes out into the open atmosphere very rap...
Two identical samples of the same ideal gas are kept at the same temperature but stored at very diff...
Two identical samples of the same ideal gas are kept at the same temperature but stored at very diff...
Two moles of an ideal gas expand isothermally at 300 K from a volume V to a volume 2V in a slow reve...
Two moles of an ideal gas expand isothermally at 300 K from a volume V to a volume 2V in a slow reve...
On a pressure-volume diagram an isothermal curve and an adiabatic curve pass through the same point ...
On a pressure-volume diagram an isothermal curve and an adiabatic curve pass through the same point ...
For a diatomic ideal gas the molar specific heat at constant volume is 5R/2, so what is the value of...
For a diatomic ideal gas the molar specific heat at constant volume is 5R/2, so what is the value of...
An ideal gas expands at a constant pressure of 2 × 10^5 Pa, increasing its volume from 0.01 m^3 to 0...
An ideal gas expands at a constant pressure of 2 × 10^5 Pa, increasing its volume from 0.01 m^3 to 0...
A heat engine absorbs 1000 J of heat from a hot reservoir and rejects 600 J to the cold reservoir in...
A heat engine absorbs 1000 J of heat from a hot reservoir and rejects 600 J to the cold reservoir in...
Heat of 400 J is supplied to a gas sealed inside a rigid steel container whose volume cannot change,...
Heat of 400 J is supplied to a gas sealed inside a rigid steel container whose volume cannot change,...
A monatomic ideal gas with gamma equal to 5/3 expands adiabatically until its volume becomes 8 times...
A monatomic ideal gas with gamma equal to 5/3 expands adiabatically until its volume becomes 8 times...
A gas confined in a perfectly insulated cylinder is suddenly compressed by a fast-moving piston, so ...
A gas confined in a perfectly insulated cylinder is suddenly compressed by a fast-moving piston, so ...
About This Question
- Subject
- physics
- Chapter
- thermodynamics
- Topic
- heat pump and energy transfer
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
600 J
As presented in NCERT Class 11, Chapter 12 (Thermodynamics), a heat pump is a device that transfers heat from a colder region to a warmer region using work input, and it obeys energy conservation in the form QH=QC+W. Here the heat delivered to the warm room is QH=800 J and the work input is W=200 J, so the heat extracted from the cold outside air is QC=QH−W=800−200=600 J. The option 800 J is wrong because that is the total heat delivered, which already includes the work converted to heat. The option 1000 J is wrong because it adds the work to the delivered heat instead of subtracting, violating the energy balance. The option 400 J is wrong because it subtracts twice the work or otherwise mishandles the conservation equation. A plausibility check: the heat delivered to the warm side must always exceed the heat drawn from the cold side by exactly the work input, and indeed 800=600+200 balances perfectly, confirming both the sign convention and the magnitude.
This easy difficulty physics question is from the chapter thermodynamics, covering the topic of heat pump and energy transfer. It appeared in the 2025 exam.
Looking for more practice? Explore all physics questions or browse thermodynamics questions on RankGuru.