The momentum of a photon having energy $hv$ is ............

There are $n_1$ photons of frequency $\nu_1$ in a beam of light. In an equally energetic beam,there are $n_2$ photons of frequency $\nu_2$. Then the correct relation is

Assertion: Mass of a moving photon varies inversely as the wavelength.
Reason: Energy of the particle $= \text{mass} \times (\text{speed of light})^2$

Find the number of photons emitted per second by a $100 \ W$ bulb emitting light of wavelength $540 \ nm$. (Given: $h = 6 \times 10^{-34} \ J \cdot s$)

The momentum of a photon of energy $1 \, MeV$ in $kg \, m/s$ will be:

$A$ source $S_1$ is producing $10^{15}$ photons per second of wavelength $5000 \; \mathring{A}$. Another source $S_2$ is producing $1.02 \times 10^{15}$ photons per second of wavelength $5100 \; \mathring{A}$. Then,$(\text{power of } S_2) / (\text{power of } S_1)$ is equal to