A spherical black body with a radius of 12 cm radiates 450

A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be :

Given r₁ = 12 cm , r₂ = 6 cm
T₁ = 500 K and T₂ = 2 × 500 = 1000 K
P₁ = 450 watt
Rate of power loss P ∝ r² T⁴

	P₁	=	r₁²T₁⁴
	P₂		r₂²T₂⁴

P₂ = P₁	r₂²T₂⁴
	t₁ - t₁⁴

Solving we get, P₂ = 1800 watt