Question

In radiation heat transfer, the Stefan–Boltzmann constant (\(\sigma\)) is used in the equation for:

• A. Thermal diffusivity
• B. The rate of heat loss by convection
• C. The total radiation emitted by a black body
• D. The rate of heat transfer by conduction

Hint:

When you see the Stefan–Boltzmann constant (\(\sigma\)), think of radiative heat transfer and black body emission.

Answer 1

The Correct Option is C

The Stefan–Boltzmann law describes the power radiated from a black body in terms of its temperature. The equation is: \[ E = \sigma T^4 \] Where:
\( E \) = emissive power (energy radiated per unit area)
\( \sigma \) = Stefan–Boltzmann constant \((5.67 \times 10^{-8} \, \text{W/m}^2\text{K}^4)\)
\( T \) = absolute temperature in Kelvin
This law is fundamental in thermal radiation theory and applies specifically to black bodies, which are idealized physical bodies that absorb all incident radiation.
Therefore, the Stefan–Boltzmann constant is used in calculating the total radiation emitted by a black body.