Heat energy is incident on the surface at the rate of 1000J/min. If coefficient of absorption is 0.8 and coefficient of reflection is 0.1 then heat energy transmitted by the surface in 5 minutes is

Physics | Physics

100J
500J
700J
900J

Solution: The correct answer is 2. 500 J

Let, the heat transmitted per minute be given by $H.$ Now,

The total incident energy = energy absorbed + energy reflected + energy transmitted

$1000 = 0.8 \times 1000 + 0.1 \times 1000 + H$

$H = 100 J / m i n$

Heat energy transmitted in 5 minutes = $100 \times 5 = 500 J$

i

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