Physics Circle home Student Login

Home›Chapters›Heat Transfer and Radiation PYQs›Thermal Radiation: Black Body, Stefan & Wien›Question 50

MHT CET 2025 (26 Apr, Shift 2) · Thermal Radiation: Black Body, Stefan & Wien

Thermal Radiation: Black Body, Stefan & Wien question from MHT CET 2025 (26 Apr, Shift 2)

Q50MHT CET 2025 · 26 APR · SHIFT 2Medium

Thermal Radiation: Black Body, Stefan & Wien

A black sphere has radius RR whose rate of radiation is E at temperature T. If radius is made R / 2 and temperature 3T, the rate of radiation will be

Show answer and solution

Answer: (c)

  1. Rate of radiation E=4πR2σT4∝R2T4E = 4\pi R^2 \sigma T^4 \propto R^2 T^4.
  2. E′E=(12)2(3)4=814\dfrac{E'}{E} = \left(\dfrac{1}{2}\right)^2 (3)^4 = \dfrac{81}{4}
  3. So the answer is (c) 81E4\dfrac{81E}{4}.
Report a mistake

More questions on Thermal Radiation: Black Body, Stefan & Wien