Question

A black body at 200 K is found to emit maximum energy at a wavelength 14μm. When its temperature is raised to 1000K, then wavelength at which maximum energy emitted it?

(a) 14mm

(b) 7μm

(c) 2.8μm

(d) 28mm

This question was addressed to me during an online exam.

My doubt is from Absorption and Emission topic in chapter Kinetic Theory of Gases of Engineering Physics I

Answer 1

Correct answer is (c) 2.8μm

To elaborate: By Wien’s law,

200×14=100×T^‘

T^‘=2.8μm.