physics help please!!!!?

Question

Given that an object has an emissivity of .75 and an area of .20m^2 , how much energy does it radiate outward per second at 20C?

please help me solve it and please show the work to

Answer 1

Energy radiated per second is given by
E = e*sigma*A*T^4 where
e = emissivity;
sigma = Stefan's constant = 5.67 * 10^-8 W/m^2/K^4
A = surface area
T = temperature in kelvin.
Substituting the various values,
E = 249 * 10^-8 Watts.