NEET Physics Question - Thermal Physics

For a black body at temperature $727^{\circ}\text{C}$, its radiating power is $60 \text{ watt}$ and temperature of surrounding is $227^{\circ}\text{C}$. If temperature of black body is changed to $1227^{\circ}\text{C}$ then its radiating power will be: (2002)

$304 \text{ W}$

$320 \text{ W}$

$240 \text{ W}$

$120 \text{ W}$

Solution:

Radiating power $P = \sigma A (T^4 - T_0^4)$. $\frac{P_2}{P_1} = \frac{T_2^4 - T_0^4}{T_1^4 - T_0^4} = \frac{1500^4 - 500^4}{1000^4 - 500^4} = \frac{3^4 - 1^4}{2^4 - 1^4} = \frac{80}{15} = \frac{16}{3}$. $P_2 = \frac{16}{3} \times 60 = 320 \text{ W}$.

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Solution:

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