Question

Light has wavelength $600\, nm$ in free space. It passes into glass, which has an index of refraction of $1.50,$ What is the frequency of the light inside the glass ?

• A. $3.3 \times 10^{14} Hz $
• B. $5.0 \times 10^{14} Hz $
• C. $3.3 \times 10^{5} Hz $
• D. $5.0 \times 10^{5} Hz $

Answer 1

Answer: (B)

Given, wavelength of light $=600\, nm$
$=600\times 10^{9}\,m$
$n=1.5$
As the frequency of light cannot change, $c=v\lambda$
Speed of light in free space $=3\times10^{8}m/ s$
$\therefore 3\times10^{8}=v\times600\times10^{9}$
$\Rightarrow v=\frac{3\times10^{8}}{600\times10^{-9}}$
$=5\times10^{14}\,HZ$