If the absolute temperature of a blackbody is increased by a factor 3,

1.	If the absolute temperature of a blackbody is increased by a factor 3, the energy radiated by it per unit time per unit area will increase by a factor of (A) 9 (B) 27 (C) 81 (D) 243.
Answer» Correct Option is (C) 81 Stefan Boltzman law : \(\theta = \sigma AT^4\) then, \(\frac{\theta _1}{\theta_2} = \frac{T_1 {^4}}{T_2{^4}}\) \(\frac{\theta_2}{\theta _1} = \frac{T_2{^4}}{T_1 {^4}}\) \(\frac{\theta_2}{\theta _1} = \frac{3T_1{^4}}{T_1{^4}}\) \(\theta_2 = 81 \ \theta _1 \) Correct option is (C) 81

If the absolute temperature of a blackbody is increased by a factor 3, the energy radiated by it per unit time per unit area will increase by a factor of (A) 9 (B) 27 (C) 81 (D) 243.

Answer»

Correct Option is (C) 81

Stefan Boltzman law : \(\theta = \sigma AT^4\)

then,

\(\frac{\theta _1}{\theta_2} = \frac{T_1 {^4}}{T_2{^4}}\)

\(\frac{\theta_2}{\theta _1} = \frac{T_2{^4}}{T_1 {^4}}\)

\(\frac{\theta_2}{\theta _1} = \frac{3T_1{^4}}{T_1{^4}}\)

\(\theta_2 = 81 \ \theta _1 \)

Correct option is (C) 81