What is the charge on $\gamma$-rays?

Work function $(W_0)$ values of six metals (in $eV$) are given below: $Li: 2.42, Mg: 3.7, Cu: 4.8, Ag: 4.3, K: 2.25, Na: 2.3$. How many of the above metals do not eject the electrons when they are made to strike with radiation of wavelength $400 \text{ nm}$? $(h = 6.62 \times 10^{-34} \text{ Js})$

The frequency of an electromagnetic radiation is $2 \times 10^6 \ Hz$. What is its wavelength in metres? (Velocity of light $= 3 \times 10^8 \ m \ s^{-1}$)

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

The velocity of $\alpha-$rays is approximately

Give the characteristics of electromagnetic radiation. Give the relation between them.