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A body at a temperature of 727^(@)C and ...

A body at a temperature of `727^(@)C` and having surface area `5 cm^(2)`, radiations `300 J` of energy each minute. The emissivity is(Given Boltzmann constant `=5.67xx10^(-8) Wm^(-2)K^(-4)`

A

e = 0.18

B

e = 0.02

C

e = 0.2

D

e = 0.15

Text Solution

Verified by Experts

The correct Answer is:
D
As `Q =esigmaT^4` At
So `e=Q/(sigmaT^4 "At")=300/((5-67xx10^(-8))xx(1001)^4xx(5xx10^(04))xx60)`
= 0.18
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