Question

Quanta Question

Sketch on one set of axes how the measured kinetic energy of ejected photoelectrons might depend on the frequency of incident light for several different materials. Label the axes with representative values.

Answer 1

If the energy of the incident photon is greater than the threshold energy required for emission of electrons from the metal surface (work function of the metal), the rest of the energy is given off as kinetic energy to the ejected electrons.

where is the work function of the metal.

this is of the form: y = mx + c

where m is the slope and c is the y intercept

similarly, the slope here is: m = h and y intercept is: c = -

so, if frequency vs kinetic energy is plotted such that the frequency of the incident radiation is on the horizontal axis and the kinetic energy of the ejected electrons is on the vertical axis, then the graph will be a straight line of slope equal to the Planck's constant.

For every metal, the slope will remain the same. However, the y intercept will not be the same since each metal has a different work-function.