A mercury lamp is a convenient source for studying frequency dependence of photoelectric emission, since it gives a number of spectral lines ranging from the UV to the red end of the visible spectrum. In our experiment with rubindium photocell, the following lines from a mercury source were used:
`lamda_1=3650A`,`lamda_2=4047A`,`lamda_3=4358A`, `lamda_4=5461A`,and `lamda_5=6707A`
The stopping voltages, respectively, were measured to be:
`V_1=1.28V`,`V_2=0.95V`,`V_3=0.74V`,`V_4=0.16V` and `V_5=0 V`
a. Determine the value of Planck's constant h.
b. Estimate the threshold frequency and work function for the material.