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Two bodies A and B are placed in an evac...

Two bodies A and B are placed in an evacuated vessel maintained at a temperature of `27^(@)C`, the temperature of A is `327^(@)C` and that of B is `227^(@)C`. Then the ratio of heat loss by body A and B is

A

`3:2`

B

`245:1`

C

`2:1`

D

`3:1`

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The correct Answer is:
To solve the problem, we need to find the ratio of heat loss by bodies A and B using Newton's Law of Cooling. ### Step-by-Step Solution: 1. **Identify the temperatures**: - Temperature of body A, \( T_A = 327^\circ C \) - Temperature of body B, \( T_B = 227^\circ C \) - Surrounding temperature, \( T_s = 27^\circ C \) 2. **Convert temperatures to Kelvin**: - To convert Celsius to Kelvin, we use the formula: \[ T(K) = T(°C) + 273 \] - For body A: \[ T_A = 327 + 273 = 600 \, K \] - For body B: \[ T_B = 227 + 273 = 500 \, K \] - For surrounding temperature: \[ T_s = 27 + 273 = 300 \, K \] 3. **Apply Newton's Law of Cooling**: - According to Newton's Law of Cooling, the rate of heat loss \( \frac{dQ}{dt} \) is given by: \[ \frac{dQ}{dt} = k (T - T_s) \] - For body A: \[ \frac{dQ_A}{dt} = k (T_A - T_s) = k (600 - 300) = k \cdot 300 \] - For body B: \[ \frac{dQ_B}{dt} = k (T_B - T_s) = k (500 - 300) = k \cdot 200 \] 4. **Calculate the ratio of heat loss**: - Now, we can find the ratio of heat loss by A and B: \[ \frac{dQ_A/dt}{dQ_B/dt} = \frac{k \cdot 300}{k \cdot 200} = \frac{300}{200} = \frac{3}{2} \] 5. **Conclusion**: - Therefore, the ratio of heat loss by body A to body B is \( \frac{3}{2} \). ### Final Answer: The ratio of heat loss by body A and B is \( \frac{3}{2} \). ---

To solve the problem, we need to find the ratio of heat loss by bodies A and B using Newton's Law of Cooling. ### Step-by-Step Solution: 1. **Identify the temperatures**: - Temperature of body A, \( T_A = 327^\circ C \) - Temperature of body B, \( T_B = 227^\circ C \) - Surrounding temperature, \( T_s = 27^\circ C \) ...
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NIKITA PUBLICATION-KINETIC THEORY OF GASES & RADIATION -MCQs (Stefans Law of Black Body Radiation)
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  8. A body radiates heat at the rate of 50 J/s at 300 K. when the same bod...

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  10. A cube, which may be regarded as a perfectly black body, radiates heat...

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