Question

A blackbody is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U₁, at wavelength 500 nm is U₂ and that at 1000 nm is U₃. Wien's constant, b = 2.88 x 10⁶ nmK. Which of the following is correct?

Options

• U₁ > U₂

• U₂ > U₁

• U₁ = 0

• U₃ = 0

Answer 1

U₂ > U₁

Explanation:

According to Wien's displacement law,

`lambda_"max" prop 1/"T"`

`therefore lambda_"max""T" = "b"`

also T = 5760 K

`therefore  lambda_"max" = (2.88 xx 10^6  "nmK")/(5760  "K")`

`= 500  "nm"`

∴ wavelength of maximum energy = 500 nm i.e., U₂ is maximum energy.