NEET Physics Question - Thermal Physics - Heat Transfer

Assertion (A): A sphere, a cube and a thin circular plate made of same material and of same mass are initially heated to \( 200^{\circ}\text{C} \), the plate will cool at fastest rate.

Reason (R): Rate of cooling \( = \frac{\rho A \sigma}{ms} (T^4 - T_0^4) ) ( \propto \) surface area. Surface area is maximum for circular plate.

Both (A) & (R) are true and the (R) is the correct explanation of the (A)

Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(A) is true but (R) is false

Both (A) and (R) are false

Solution:

Assertion (A) is true because a thin plate has a larger surface area-to-mass ratio. Reason (R) states cooling rate \( \propto \) surface area, which is true \( \frac{dT}{dt} \propto \frac{A}{m}) \), and that a plate has the maximum surface area (for a given mass). Thus, both are true and (R) correctly explains (A).

Rankers Physics

Cooling Rate of Different Shapes

Solution:

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