Which emission transition series is obtained when an electron jumps from $n_2 = \infty$ to $n_1 = 1$?

The radiation is emitted when a hydrogen atom goes from a high energy state to a lower energy state. The wavelength of one line in the visible region of the atomic spectrum of hydrogen is $6.5 \times 10^{-7} \, m$. The energy difference between the two states is:

The frequency of yellow light having wavelength $600 \ nm$ is

Which color in the visible spectrum has the maximum energy? Provide its energy,wavelength,and frequency.

If light waves pass through a $Nicol$ prism,then all the oscillations occur only in one plane. Such a beam of light is called:

What is the wavelength for a wave having frequency $50 \ Hz$?