The frequency of a photon with energy $100 \ eV$ is ........... $Hz$. (Given: $h = 6.62 \times 10^{-34} \ J \cdot s$,$1 \ eV = 1.6 \times 10^{-19} \ J$)

The radiant energy from the Sun incident on the Earth's surface is $2 \ cal/cm^2 \cdot min$. If the average wavelength of solar radiation is $5500 \ \mathring A$,then the number of photons incident per minute on a surface area of $1 \ cm^2$ on the Earth's surface is ............ $(h = 6.6 \times 10^{-34} \ J \cdot s, 1 \ cal = 4.2 \ J)$

If $n_r$ and $n_b$ are the number of photons emitted per second by a red bulb and a blue bulb of equal power respectively,then:

The value of Planck's constant is

The momentum of a photon of energy $h\nu$ will be:

If $E$ and $P$ are the energy and the momentum of a photon respectively,then on reducing the wavelength of the photon: