The temperature T of a plate changes with time t as T Tot14

The temperature T of a plate changes with time t as T = T_ot^1/4 where the constant T_o is in absolute temperature. How does the blackbody emissive power of the plate change with time? A blackbody at 30 degree C is heated to 80 degree C. Calculate the increase in its emissive power.

Solution

1-26.

For black body emissive power (E) is given by A T⁴

where = stefan- Boltzmann constant, W/m²K^-4

A = Area about which radiation takes place, m²

T = Temperature of plate, K

As T= T₀t^1/4

Emissive power, E = A T⁴

= A (T₀ t^1/4)⁴

= A T₀ ⁴ t

here except t, all others are constant ( A T₀)

so, we can say that Emissive power is directly proportional to time t.