The ratio of energies of photons with wavelengths $\lambda_1 = 150 \ nm$ and $\lambda_2 = 300 \ nm$ is:

$A$ radio transmitter transmits at a frequency of $880 \ kHz$ and consumes $10 \ kW$ of power. The number of photons emitted per second from the transmitter is:

The momentum of a photon with frequency $1.5 \times 10^{13} \ Hz$ is .......

Two sources of light emit with a power of $200 \ W$. The ratio of the number of photons of visible light emitted per second by each source having wavelengths $300 \ nm$ and $500 \ nm$ respectively,will be:

An electron and a photon have the same wavelength of $10^{-9} \, m$. If $E$ is the energy of the photon and $p$ is the momentum of the electron,then the magnitude of $E / p$ (in $SI$ unit) is

The idea of the quantum nature of light has emerged in an attempt to explain: