Question

The part of the electromagnetic spectrum to which 2.7 K belongs is

• A. radio
• B. microwave
• C. X-ray
• D. y-rays

Answer 1

Answer: (B)

microwave

Answer 2

Using the relation $\lambda_m\,T=0.29 cm K$ ( Wien's displacement law)$\lambda_m=\frac{0.29}{T}=\frac{0.29}{2.7}=0.11 cm$ Part of the e.m. spectrum for this wavelength is 'microwave'.