The refractive index of air with respect to vacuum is . . . . . . .

Find the refractive index of glass from the given figure,where the refractive index of water is $\mu_w = 4/3$.

$A$ monochromatic light wave with wavelength $\lambda_1$ and frequency $v_1$ in air enters another medium. If the angle of incidence and angle of refraction at the interface are $45^{\circ}$ and $30^{\circ}$ respectively,then the wavelength $\lambda_2$ and frequency $v_2$ of the refracted wave are :

Electromagnetic radiation of frequency $n$,wavelength $\lambda$,travelling with velocity $v$ in air,enters a glass slab of refractive index $\mu$. The frequency,wavelength,and velocity of light in the glass slab will be respectively:

Which of the following statements is true?

When a light ray enters from medium $i$ to medium $j$,if $_i\mu_j$ represents the refractive index,what is the product of $_2\mu_1 \times _3\mu_2 \times _4\mu_3$?