The famous Stefans law of radiation states that the rate of emission of thermal radiation per unit

by a black body is proportional to the area and the fourth power of its absolute temperature that is

Q = α AT4 where A = area, T = temperature and cr is a universal constant. In the energy- length time

temperature (E-L-T-K) system the dimension of α is?

(1) E²T²L^-2K^-2

(2) E^-1T^-2L^-2K^-1

(3) ET^-1 L^-3K^-4

(4) ET^-1 L^{- 2}K^-4