Calculate the amount of heat radiated per second by a body of surface area 12 cm 2 kept in thermal equilibrium in a room at temperature 20°C. The emissivity of the surface = 0.80 and σ = 6.0 × 10 −8 W m −2 K −4 .

Question

Philoid · Accepted Answer

Given

Area of the body, A = 12 × 10⁻⁴ m²

Temperature of the body, T =20°C

= (273 + 20) K

= 293 K

Emissivity of the surface, e = 0.80

Stefan-Boltzmann constant σ = 6.0 × 10⁻⁸ W m⁻² K⁻⁴.

Now

Rate of emission of heat is given by-

R = AeσT⁴

Where

A = Area of the surface

e = Emissivity of the surface

σ = Stefan-Boltzmann constant

And T = temperature

Substituting the values -

⇒ R = 12 × 10⁻⁴ × 0.80 × 6.0 × 10⁻⁸ × (293)⁴

⇒ R = 0.42 J

Calculate the amount of heat radiated per second by a body of surface area 12 cm2 kept in thermal equilibrium in a room at temperature 20°C. The emissivity of the surface = 0.80 and σ = 6.0 × 10−8 W m−2 K−4.

Calculate the amount of heat radiated per second by a body of surface area 12 cm² kept in thermal equilibrium in a room at temperature 20°C. The emissivity of the surface = 0.80 and σ = 6.0 × 10⁻⁸ W m⁻² K⁻⁴.