A wave of light having frequency `4 xx 10^(14)`Hz. And speed of light `3 xx 10^8` m/s enters glass of R.I. 1.5. Change in wavelength is

Options

A. `2.5 xx 10^(-7) m`
B. `2.5 xx 10^(-6) m`
C. `2.5 xx 10^(-8)m`
D. `2.5 xx 10^(-9)m`

Answer

A

Explanation

`lambda_(a) = (v_(a))/(n) = (3 xx 10^(8))/(4 xx 10^(14)) = 0.75 xx 10^(-6)`
`= 7500 Å`
`lambda_(g) = (lambda_(a))/(mu_(g)) = (7500)/(1.5) = 5000Å`
`lambda_(a) - lambda_(g) = 7500 - 5000 = 2500 Å`