BPSC CCE Prelims
Heat and Thermodynamics Previous Year Questions (PYQs)
Practice solved questions for Heat and Thermodynamics with detailed step-by-step solutions, key insights, and trend analysis for BPSC CCE PRELIMS.
Solved Previous Year Questions
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Heat transfer that does not require a medium is called:
Detailed Explanation:
Radiation is the mode of heat transfer that does not require any material medium (solid, liquid, or gas).
It travels through electromagnetic waves (infrared rays) and can occur in vacuum, such as the Sun's heat reaching Earth through empty space.
Due to temperature variation along a conductor, potential variation occurs along it. This phenomenon is known as
Detailed Explanation:
The Thomson effect describes the generation of electromotive force (EMF) in a single conductor due to a temperature gradient along its length.
- Core Distinction: Unlike the Seebeck effect (requiring two dissimilar metals), Thomson effect occurs in a single homogeneous conductor with varying temperature.
- Mechanism: Electrons diffuse from hot to cold regions, creating a potential difference proportional to the temperature gradient.
- Therefore, potential variation due to temperature variation in a single conductor is the Thomson effect, making Option 4 the correct answer.
A fan produces a feeling of comfort during the hot weather because
Detailed Explanation:
A fan creates air movement that accelerates the evaporation of perspiration from our skin. This evaporation is an endothermic process that absorbs heat from the body, producing a cooling sensation.
The fan does not supply cool air (it merely circulates room-temperature air), nor does it significantly alter body heat radiation or air conductivity—it purely enhances evaporative cooling.
Therefore, perspiration evaporates rapidly, making Option 4 the correct answer.
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Food gets cooked faster in a pressure cooker because
Detailed Explanation:
In a pressure cooker, the sealed environment increases internal pressure, which raises the boiling point of water above the normal 100°C (at atmospheric pressure). Water boils at a higher temperature (~120°C), transferring more heat energy to food, cooking it faster.
Options 1 and 3 incorrectly state boiling occurs at low temperature, while option 4 wrongly claims low pressure inside the cooker.
Therefore, water boils at high temperature due to high pressure, making Option 2 the correct answer.
If the doors of a refrigerator are left open for few hours, then the room temperature will
Detailed Explanation:
A refrigerator operates on the Second Law of Thermodynamics: it removes heat from inside and releases it (plus compressor work energy) outside. With doors open, heat expelled into the room exceeds heat absorbed from the room, causing a net temperature increase.
The compressor converts electrical energy into heat, adding extra thermal energy to the room. The cooling effect is localized and temporary, while the heating effect is continuous and distributed.
Therefore, the room temperature will increase, making Option 2 the correct answer.
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Common questions about Heat and Thermodynamics in BPSC CCE PRELIMS