An AIR station is broadcasting the waves of wavelength $300$ metres. If the radiating power of the transmitter is $10 kW$, then the number of photons radiated per second is
$1.5 \times {10^{29}}$
$1.5 \times {10^{31}}$
$1.5 \times {10^{33}}$
$1.5 \times {10^{35}}$
A photon falls through a height of $1 \,km$ through the earth's gravitational field. To calculate the change in its frequency, take its mass to be $h v / c^{2}$. The fractional change in frequency $v$ is close to
Light of wavelength $5000\,\,\mathop A\limits^o $ falling on a sensitive surface. If the surface has received $10^{-7}\,J$ of energy, then the number of photons falling on the surface will be
Given below are two statements
Statement$-I :$ Two photons having equal linear momenta have equal wavelengths.
Statement$-II :$ If the wavelength of photon is decreased, then the momentum and energy of a photon will also decrease.
In the light of the above statements, choose the correct answer from the options given below.
The photo-electrons emitted from a surface of sodium metal are such that
Monochromatic light of frequency $6 \times 10^{14} \mathrm{~Hz}$ is produced by a laser. The power emitted is $2 \times 10^{-3} \mathrm{~W}$. How many photons per second on an average, are emitted by the source?
(Given $\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}$ )