Question

Assuming that a given star radiates like a blackbody,
estimate
(i) the temperature at its surface and
(ii) the wavelength of its strongest radiation, when it emits a total intensity of 575MWm−2.

Answer 1

Answer:

the wavelength of its strongest radiation, when it emits a total intensity of 575MWm−2.

Answer 2

Given info : Assuming that a given star, radiates like a blackbody.

To estimate : (I) the temperature at its surface and

(ii) the wavelength of its strongest radiation, when it emits a total intensity of 575 W/m².

Solution : from Stefan Boltzmann's law, I = σT⁴

⇒575 W/m² = 5.68 × 10^-8 W/m²/K⁴ × T⁴

⇒(5.75/5.68) × 10¹⁰ = T⁴

⇒T ≈ 317 K

So temperature of the surface of blackbody is 317K.

(ii) Using Wien displacement law, λT = b

Where b = 2.898 × 10¯³ mK

Here, T = 317 K

So, λ = 2.898 × 10¯³/317 = 0.00914 × 10¯³ m = 9.14 μ m

therefore the wavelength of its strongest radiation is 9.14μm.