While passing through an applied magnetic field,which of the following undergoes the maximum deflection?

Yellow light emitted from a sodium lamp has a wavelength $(\lambda)$ of $580 \,nm$. Calculate the frequency $(v)$ and wave number $(\bar{v})$ of the yellow light.

In which type of radiation do the mass number and atomic number remain unchanged?

Consider a helium $(He)$ atom that absorbs a photon of wavelength $330 \ nm$. The change in the velocity (in $cm \ s^{-1}$) of the $He$ atom after the photon absorption is . . . . . .
(Assume: Momentum is conserved when the photon is absorbed. Use: Planck constant $= 6.6 \times 10^{-34} \ J \ s$,Avogadro number $= 6 \times 10^{23} \ mol^{-1}$,Molar mass of $He = 4 \ g \ mol^{-1}$)

The energy of an electromagnetic radiation is $19.875 \times 10^{-13} \ erg$. What is its wave number in $cm^{-1}$? $(h = 6.625 \times 10^{-27} \ erg \ sec, c = 3 \times 10^{10} \ cm \ sec^{-1})$

Energy of a photon is $1 \ MeV,$ then its momentum will be $:-$