The wavefront due to a source situated at infinity is

During the reflection of light from the plane mirror, the incident ray, normal and reflected ray lie

The laws of reflection of light are valid for

When light enters from air to water, then its

Which one of the following statements is correct?

The refractive index of a given piece of glass is

Light of a certain wavelength has a wave number $v$ in a vacuum. Its wave number in a medium of refractive index $n$ is

A ray of light travelling in the air has the wavelength $\lambda$, frequency $n$, velocity $v$ and intensity $I$. If this ray enters into water, then these parameters are ${\lambda }^{\text{'}}$, $n^{\text{'}}$, $v^{\text{'}}$ and $I^{\text{'}}$, respectively. Which relation is correct from the following?