If the momentum of a photon is $p$,then its frequency is ........

The value of Planck's constant is

$A$ 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

If the energy of a photon is expressed in units of $KeV$ and the wavelength in units of $\mathring{A}$,then the energy of the photon can be calculated by:

$A$ stick of $1 \, m$ is moving with a velocity of $2.7 \times 10^8 \, m/s$. What is the apparent length of the stick in meters? (Given: $c = 3 \times 10^8 \, m/s$)

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