Question

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