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How many watts of energy is required to ...

How many watts of energy is required to keep a black body in the form of a cube of side 1 cm at 2000 K ? (Temperature of surrounding is `27^(@)C` and `sigma=5.67xx10^(-8)"W m"^(-2)K^(-4)` ) :

A

444 W

B

544 W

C

844 W

D

None of the above

Text Solution

Verified by Experts

The correct Answer is:
B
Area `A=6l^(2)=6cm^(2)=6xx10^(-4)m^(2)`.
`E=sigma(T^(4)-T_(0)^(4))A=5*67xx10^(-8)[(2000)^(4)-(300)^(4)]xx6xx10^(-4)`.
`E=544` warr.
Thus correct choice is (b).
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