Two spheres made of same material have radii in the ratio $1: 2$ Both are at same temperature. Ratio of heat radiation energy emitted per second by them is
A$1:2$
B$1:8$
C$1:4$
D$1:16$
Medium
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C$1:4$
c (c) $Q = A\varepsilon \sigma {T^4}$
==> $Q \propto A \propto {r^2}$ ( $\because T =$ constant)
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