Question

Red light of wavelength `750 nm` enters a glass plate of refractive index `1.5`. If velocity of light in vacuum is `3 xx 10^(8) m//s`, calculate velocity, wavelength and frequency of light in glass.
A. ` 2.5xx10^(-6) m`
B. `2.5xx10^(-7) m`
C. `2.5xx10^(-8) m`
D. `2.5xx10^(-9) m`

Answer 1

Correct Answer - B
`lambda_a=(V_(a))/(n)=( 3 xx 10^(8))/( 4 xx 10^(14))=7.5 xx 10^(-7) m and lambda_g=(lambda_a)/(1.5)=5 xx 10^(-7)m`
`:. ` Change in wavelength `=2.5 xx 10^(-7)m`