A ray of light has speed `v_(0)`, frequency `f_(0)` a wavelength `lambda_(0)` in vacuum. When this ray of light enters in a medium of refractive index corresponding values are v, f and `lambda`. Then

Options

A. its wavelength increases, frequency decreases
B. its wavelength decreases, frequency remains same
C. its wavelength increases, frequency remains same
D. `Delta lambda = lambda_(0) ((1)/(mu) - 1)` and `Delta upsilon = 0`

Answer

b.,d

Explanation

Whenever a ray goes from one medium to another, its frequency remains same. Its wavelength changes in accordance
with `mu lambda =` constant. i.e.,
`mu_(0) lambda)(0) = mu lambda` `(because mu_(0) = mu_("air") = 1)`
`lambda = (lambda_(0))/(mu) (lt lambda)`
So, `lambda` decreases when it goes from rarer to denser medium and vice versa.
`Delta lambda = lambda - lambda_(0)`
`Delta lambda = lambda_(0) ((1)/(mu) - 1)`