Heat energy is incident on the surface at the rate of $1000 \mathrm{~J} / \mathrm{min}$. If coefficient of…

Heat energy is incident on the surface at the rate of $1000 \mathrm{~J} / \mathrm{min}$. If coefficient of absorption is 0.8 and coefficient of reflection is 0.1 , then heat energy transmitted by the surface in 5 minute is
  1. 700 J
  2. 500 J
  3. 100 J
  4. 900 J

Solution

Considering energy conservation: Coe. of transmission +Coe. of absorption +Coe. of reflection $=1$ Therefore, Coefficient of transmission $=1-0.8-0.1=0.1$ It means $10 \%$ of incident energy will be transmitted. Hence transmitted energy in $5 \mathrm{~min}$ $=1000 \times 0.1 \times 5=500 \mathrm{~J}$

Asked in: MHT CET 2022 (11 Aug Shift 1)

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