Question

1. If the surface temperature of a blue star is 25000 K, at what wavelength would it emit most of its light and which part of the electromagnetic spectrum would that light be?
2. Calculate the surface temperature of an X-ray star which emits at 1nm peak wavelength?

Answer 1

Given :

Part 1:

Temperature of star = 25000 k.

Wavelength of blue star max is given by formula:

  (from WIEN'S DISPLACEMENT LAW)

  

NOTE : The above formula is written so that if you put T in kelvin , one will get back maximum wavelength in nanometer.

and this come in the ULTRAVIOLET part of electromagnetic spectrum.

Part 2 :

As we know that ,

so, we have  max = 1nm.

therefore,

  

Hence putting max = 1nm we get,

Hence,The surface temperature of an X-ray star which emits at 1nm peak wavelength = 2,900,000 k