Question

Monochromatic light of frequency $5\times 10^{14}Hz$ travelling in vacuum enters medium of refractive index $1.5$. Its wavelength in the medium is

• A. $4000\mathring{A}$
• B. $5000\mathring{A}$
• C. $6000\mathring{A}$
• D. $5500\mathring{A}$

Answer 1

Answer: (A)

Frequency $(f)=5\times 10^{14}Hz$
$\therefore$ Wavelength of light
$(\lambda )=\frac{c}{f}=\frac{3\times 10^8}{5\times 10^{14}}$
$=6\times 10^{-7}m=6000\mathring{A}$
$\therefore$ Wavelength in medium of refractive index
${\lambda }^{\prime }=\frac{\lambda }{\mu }=\frac{6000}{1.5}=4000\mathring{A}$