NEET Physics — Dual Nature of Matter

A light source emits $5.0 \times 10^{15}$ photons per second with a power of $2.0 \, \text{mW}$. What is the energy of each photon in joules?

The threshold frequency of a metal is $6.0 \times 10^{14} \, \text{Hz}$. What is its work function in eV? (Take $h = 6.63 \times 10^{-34} \, \text{J s}$, $1 \, \text{eV} = 1.6 \times 10^{-19} \, \text{J}$)

The minimum wavelength of X-rays from a $15 \, \text{kV}$ tube is: (Take $h = 6.63 \times 10^{-34} \, \text{J s}$, $c = 3 \times 10^8 \, \text{m/s}$, $e = 1.6 \times 10^{-19} \, \text{C}$)

In the photoelectric effect, what does the saturation current depend on, assuming a fixed frequency above the threshold?

The maximum frequency of X-rays from a $35 \, \text{kV}$ tube is: (Take $h = 6.63 \times 10^{-34} \, \text{J s}$, $e = 1.6 \times 10^{-19} \, \text{C}$)