Practice questions

The work function for silver is $4\mathrm{.}3eV.$

a$.$ Calculate the photoelectric threshold frequency for silver.

Electromagnetic radiation of wavelength $240nm$ is incident on the silver surface.

b$.$ Calculate, for the electrons emitted from the sliver surface, their maximum:

i$.$ kinetic energy

ii$.$ speed.

c$.$ The intensity of the radiation is increased. State the effect of this change on:

i$.$ the maximum speed of the photoelectrons

ii the rate at which the electrons are emitted from the surface.

Monochromatic electromagnetic radiation is incident on a photoelectric cell with a sodium cathode, causing the emission of photoelectrons. A potential difference of at least $1\mathrm{.}5$ V applied across the cell prevents the photoelectric current from flowing in the cell.

Work function for sodium $=2\mathrm{.}3eV.$

a$.$ Calculate the maximum initial speed of the electrons emitted from the sodium surface.

b$.$ Determine the wavelength of the incident radiation.

The photoelectric threshold wavelength for a particular metal surface is $480nm.$

a$.$ Calculate, in $eV,$ the work function of the metal.

b$.$ Radiation of frequency $9\mathrm{.}0{10}^{14}Hz$ is incident on the surface. Calculate the stopping voltage for this frequency.