Question

A black body at 200K found to emit maximum radiation energy at a wavelength of 14um. When its temperature is raised to 1000K, the wavelength at which maximum energy is emitted is


(1) 14 um
(3)2.8 um
(2) 70 um
(4) 7 um​

Answer 1

Applying Wien's displacement law, λT=constant

where, λ =wavelength of maximum energy, T=absolute temperature

Let λ

1

be required wavelength at 1000K

⇒λ

1

×1000=14×200⇒λ

1

=2.8μm