Heat and Thermodynamics 3 Question 35
35. Two spheres of the same material have radii $1 m$ and $4 m$, temperature $4000 K$ and $2000 K$ respectively. The energy radiated per second by the first sphere is greater than that by the second.
(1988, 2M)
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Answer:
Correct Answer: 35. F
Solution:
- Energy radiated per second $\propto A T^{4} \propto\left(R^{2}\right) T^{4}$
$$ \frac{E _1}{E _2}=\left(\frac{1}{4}\right)^{2}\left(\frac{4000}{2000}\right)^{4}=1 \text { or } E _1=E _2 $$
