The momentum of a photon is $2 \times {10^{ - 16}}gm-cm/sec$. Its energy is

A radio transmitter operates at a frequency of $880 \,kHz$ and a power of $10\,kW$. The number of photons emitted per second are

When light of a given wavelength is incident on a metallic surface, the minimum potential needed to stop the emitted photoelectrons is $6.0 V$. This potential drops to $0.6 V$ if another source with wavelength four times that of the first one and intensity half of the first one is used. What are the wavelength of the first source and the work function of the metal, respectively? $\left[\right.$ Take $\left.=\frac{h c}{c}=1.24 \times 10^{-6} Jm ^{-1}.\right]$

How many photons are emitted by a laser source of $5 \times 10^{-3} \,W$ operating at $632.2 \,nm$ in $2 \,s$ is .......$\times 10^{16}$ $\left(h=6.63 \times 10^{-34} \,Js \right)$

If the two metals $A$ and $B$ are exposed to radiation of wavelength $350\,nm$. The work functions of metals $A$ and $B$ are $4.8\,eV$ and $2.2\,eV$. Then choose the correct option

Photo cells are used for the