A black body emits heat at the rate of $20\, W$. When its temperature is $727^{\circ} C$. Another black body emits heat at the rate of $15\, W$, when its temperature is $227^{\circ} C$. Compare the area of the surface of the two bodies, if the surrounding is at NTP.
- $ 16:1 $
- $ 1:4 $
- $ 12:1 $
- $ 1:12 $
The Correct Option is D
Solution and Explanation
Top Questions on Heat Transfer
- Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Houses made of concrete roofs overlaid with foam keep the room hotter during summer.
Reason R: The layer of foam insulation prohibits heat transfer, as it contains air pockets.
In the light of the above statements, choose the correct answer from the options given below.- NEET (UG) - 2024
- Physics
- Heat Transfer
- In given circuit, reading of voltmeter is 1 V, then resistance of
- JEE Main - 2024
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- A solid slab of thickness \( H1 \) is initially at a uniform temperature \( T0 \). At time \( t = 0 \), the temperature of the top surface at \( y = H1 \) is increased to \( T1 \), while the bottom surface at \( y = 0 \) is maintained at \( T0 \) for \( t \geq 0 \). Assume heat transfer occurs only in the \( y \)-direction, and all thermal properties of the slab are constant. The time required for the temperature at \( y = \frac{H1}{2} \) to reach 99% of its final steady value is \( T1 \). If the thickness of the slab is doubled to \( H2 = 2H1 \), and the time required for the temperature at \( y = \frac{H2}{2} \) to reach 99% of its final steady value is \( T2 \), then \( \frac{T2}{T1} \) is .
- GATE CH - 2024
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- Ice at temperature –10°C is converted to steam at 100°C, the curve plotted between temperature (T) and time (t) when it is being heated by constant power source is
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- The temperatures of two large parallel plates of equal emissivity are 900 K and 300 K. A reflection radiation shield of low emissivity and negligible conductive resistance is placed parallelly between them. The steady-state temperature of the shield, in K, is
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Questions Asked in AIIMS exam
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : 02 is liberated in the non-cyclic photophosphorylation.
Reason (R) : Liberation of oxygen is due to photolysis of water.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- Photosynthesis in higher plants
- Match the following column I with column II.
- AIIMS - 2019
- cloning
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : The Cro-Magnon man was the direct ancestor of the living modern man.
Reason (R) : Cro-Magnon man had slightly prognathous face.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- evolution
- Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion: Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.
Reason: Orbital velocity of a satellite is greater than its escape velocity.
In the light of the above statements, choose the correct answer from the options given below- AIIMS - 2019
- Gravitation
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : In eukaryotes, transcription occurs in nucleus.
Reason (R) : In bacteria, transcription and translation occurs in cytoplasm.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- Transcription
Concepts Used:
Heat Transfer
What is Heat Transfer?
It is defined as the movement of heat across the border of the system due to a difference in temperature between system and its surroundings.
How is Heat Transferred?
Heat can travel from one place to another in several ways. The different modes of heat transfer include:
- Conduction - Heat flows from things with higher temp to objects with lower temp.
- Convection - Movement of liquid molecules from higher temp regions to lower temp regions.
- Radiation - Radiant heat is present in every other way in our daily lives. Thermal radiations are also known to as radiant heat. Thermal radiation is generated by the emission of electromagnetic waves.
