[Agneisse]

1) Light of wavelength 389nm shines on a photocathode and elections of kinetic energy 1.45eV are given off. What is the work function (in eV and J) of the surface? What maximum wavelength of light will cause photoemission from this cathode?

2) When metallic element salts are vaporised, they often show a visible emission line. Li salts emit 671nm. Calculate delta-E in electron-volts and inverse centimetres for Li salts.

3) When Na vapour is irradiated by radiation of 121.568nm, electrons of KE 5.060eV are produced. Find the ionisation energy of Na in eV.

4) Use the Rydberg formula and Bohr's hypothesis deltaE=hc/wavelength, find a formula for the energy-level spacing between any 2 stationary states in eV.

Any and all help is greatly appreciated

[MrTeo]

Show us your attempts 

[alkufi]

all these questions is solve by Enstien relationship
                                      E = hv - w