A copper ball of radius $1 \mathrm{~cm}$ and work function $4.47 \mathrm{~eV}$ is irradiated with…
A copper ball of radius $1 \mathrm{~cm}$ and work function $4.47 \mathrm{~eV}$ is irradiated with ultraviolet radiation of wavelength $2500 ~Å$. The effect of irradiation results in the emission of electrons from the ball. Further the ball will acquire charge and due to this there will be a finite value of the potential on the ball. The charge acquired by the ball is :