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Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoRadiationMedium2 minQB

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Passage / Comprehension

A metal block remains in a room at 10°C for a long time. It is heated with a 500 W heater until it reaches 50°C. Its initial temperature-rise rate is 2.5°C/s. After the heater is switched off, a 100 W heater is needed to hold it at 50°C. Assume Newton's law of cooling.

What is the heat radiated per second when the block was 30°C?

Options:

Answer:

Solution:

$100 = k (50 - 10) \Rightarrow k = 2.5 W /^{\circ} C$
$P_{loss} (3 0^{\circ} C) = k (30 - 10) = 50 W$
Answer C.

Stream:JEESubject:PhysicsTopic:Heat & ThermoSubtopic:Radiation

⏱ 2mℹ️ Source: QB

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