(i) `mu=(c)/(v_m)=(vlambda)/(vlambda_m)`
where
c: speed of light in vacuum
`v_m:` speed of light in medium
`lambda:` wavelength in vacuum
`lambda_m`: wavelength in medium
`upsilon:` frequency of light
(ii) `mu=((epsilonmu)/(epsilon_0mu_0))^(1/2)`
where `epsilon:` electric permittivity in free space
`epsilon:` electric permittivity in medium
`mu_0:` magnetic permeability in free space
`mu:` magnetic permeability in medium
(iii) `mu=A+B/lambda^2`, where A and B are constants
(iv) In case of VIBGYOR, wavelength increases from violet to red, refractive index decreases from violet to red. Wavelength for red-colour is maximum whereas refractive index is maximum for violet colour.

Options

A. (i), (ii)
B. (ii), (iii)
C. (ii), (iii), (iv)
D. all options are correct

Answer

D