$A$ photon of wavelength $4400 \ \mathring A$ passes through a vacuum. Its effective mass and momentum are,respectively,............

$A$ proton moving with a momentum $p_{1}$ has a kinetic energy $1/8$th of its rest mass-energy. Another light photon having energy equal to the kinetic energy of the proton possesses a momentum $p_{2}$. Then,the ratio $\frac{p_{1}-p_{2}}{p_{1}}$ is equal to

Assertion: The energy $(E)$ and momentum $(p)$ of a photon are related by $p = E/c$.
Reason: The photon behaves like a particle.

Which of the following has a mass closest in value to that of the positron? $(1\;a.m.u = 931\;MeV)$

$A$ $100 \; W$ sodium lamp radiates energy uniformly in all directions. The lamp is located at the centre of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589 \; nm$.
$(a)$ What is the energy per photon associated with the sodium light?
$(b)$ At what rate are the photons delivered to the sphere?

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