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 rubidium photo-cell, the following lines from a mercury source were used: λ ₁ = 3650 Å, λ ₂= 4047 Å, λ ₃ = 4358 Å, λ₄ = 5461 Å, λ₅ = 6907 Å, The stopping voltages, respectively, were measured to be: V0₁ = 1.28 V, V0₂= 0.95 V, V0₃= 0.74 V, V0₄ = 0.16 V, V0₅ = 0 V Determine the value of Planck’s constant h, the threshold frequency and work function for the material. [Note: You will notice that to get h from the data, you will need to know e (which you can take to be 1.6 × 10⁻¹⁹C). Experiments of this kind on Na, Li, K, etc. were performed by Millikan, who, using his own value of e (from the oil-drop experiment) confirmed Einstein’s photoelectric equation and at the same time gave an independent estimate of the value of h.]