The temperature of a black body is increased by $50 \%$, then the percentage increase in the rate of…

The temperature of a black body is increased by $50 \%$, then the percentage increase in the rate of radiation by the body is approximated
  1. $50 \%$
  2. $100 \%$
  3. $400 \%$
  4. $150 \%$

Solution

Rate of radiation $\mathrm{R} \propto \mathrm{T}^4$ $\begin{aligned} & \therefore \frac{\mathrm{R}_2}{\mathrm{R}_1}=\left(\frac{\mathrm{T}_2}{\mathrm{~T}_1}\right)^4=(1.5)^4 \approx 5 \\ & \therefore \mathrm{R}_2=5 \mathrm{R}_1 \end{aligned}$ Percentage increase $=\left(\frac{\mathrm{R}_2-\mathrm{R}_1}{\mathrm{R}_1}\right) \times 100=400 \%$

Asked in: MHT CET 2021 (23 Sep Shift 2)

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