Question

the emission rate of blackbody at $0^{\circ}C$ is R then, the rate of emission at $273^{\circ}C$ is

• A. 2R
• B. 4R
• C. 8R
• D. 16R

Answer 1

Answer: (D)

16R

Answer 2

According Stefan's law, emission rate of a ideal blackbody $E \propto T^{4}$ For $T =0^{\circ} C =273\, K$ $E_{1} \propto(273)^{4}$ ...(i) For $T=273^{\circ} C =273+273=546\, K$ $E_{2} \propto(546)^{4}$ ...(ii) From Eqs. (i) and (ii), $\Rightarrow \frac{E_{1}}{E_{2}}=\left(\frac{273}{546}\right)^{4}$ $\Rightarrow \frac{R}{E_{2}}=\left(\frac{1}{2}\right)^{4}$ $\left(\because E_{1}=R\right)$ Hence, $E_{2}=16\, R$