$A$ $200\, W$ sodium street lamp emits yellow light of wavelength $0.6\, \mu m$. Assuming it to be $25\%$ efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is:

The energy $E$ and momentum $p$ of a moving body of mass $m$ are related by a specific equation. Given that $c$ represents the speed of light,identify the correct equation.

$A$ photodiode sensor is used to measure the output of a $300 W$ lamp kept $10 m$ away. The sensor has an opening of $2 cm$ in diameter. How many photons enter the sensor if the wavelength of the light is $660 nm$ and the exposure time is $100 ms$? (Assume that all the energy of the lamp is given off as light and $h = 6.6 \times 10^{-34} J s$)

If the energy of the photon is increased by a factor of $4$,then its momentum

$A$ photon in motion has a mass.

The momentum of a photon is $3.3 \times 10^{-29} \ kg \ m/s$. Its frequency will be