Alpha rays consist of a stream of

The periodic time of radiation is $4 \times 10^{-10} \ s$. Find the wavelength,wave number,and frequency.

Nitrogen laser produces a radiation at a wavelength of $337.1 \ nm$. If the number of photons emitted is $5.6 \times 10^{24}$,calculate the power of this laser.

The ....... series is observed in the visible region of the hydrogen spectrum.

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

Electromagnetic radiation of wavelength $663 \ nm$ is just sufficient to ionise the atom of metal $A.$ The ionization energy of metal $A$ in $kJ \ mol^{-1}$ is ...... .
(Rounded-off to the nearest integer) $\left[ h = 6.63 \times 10^{-34} \ Js, c = 3.00 \times 10^{8} \ ms^{-1}, N_{A} = 6.02 \times 10^{23} \ mol^{-1} \right]$