When a metal is illuminated with light of frequency

PHYSICS · Subjective · A Level · Physics · Particles and radiation · Particles and radiation

Problem

f

, the maximum kinetic energy of the photoelectrons is

1.2\,\mathrm{eV}

. When the frequency is increased by

50\%

, the maximum kinetic energy increases to

4.2\,\mathrm{eV}

. What is the threshold frequency for this metal?