A mercury lamp is a convenient souce for studying frequency dependence of photoelectric emission, since it gives a number of spectral lines ranging from the UV to the end of the red vissible spectrum. In our experiment with rubidium photocell, the following lines from a mercury source were used: `lambda_(1)=3650A^(@), lambda_(2)=4047A^(@), lambda_(3)=4358A^(@), lambda_(4)=5461A^(@), lambda_(5)=6907A^(@)` The stopping voltages, respectively were measured to be:
`V_(01)=1.28V, V_(02)=0.95V, V_(03)=0.74V, V_(04)=0.16V, V_(05)=0V`.
(a) Determine the value of Planck's constant h.
(b) Estimate the threshold frequency and work function for the material.

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: lambda_(1) = 3650 Å, lambda_(2) = 4047 Å, lambda_(3) = 4358 Å, lambda_(4) = 5461 Å, lambda_(5) = 6907 Å , The stopping voltages, respectively, were measured to be: V_(01) = 1.28 V, V_(02) = 0.95 V, V_(03) = 0.74 V, V_(04) = 0.16 V, V_(05) = 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 xx 10^(-19) C ). 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.]

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: lambda_1 = 3650 oversetcircA , lambda_2=4047 oversetcircA , lambda_3=4358 oversetcircA , lambda_4=5461 oversetcircA , lambda_5=6907 oversetcircA The stopping voltages respectively were measured to be V_0=1.28 V , V_0.95V , V_0=0.74V , V_0=0.16 , V_0=0V Determine the value of Planck's constant h.

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: lambda_1 = 3650 oversetcircA , lambda_2=4047 oversetcircA , lambda_3=4358 oversetcircA , lambda_4=5461 oversetcircA , lambda_5=6907 oversetcircA The stopping voltages respectively were measured to be V_0=1.28 V , V_0.95V , V_0=0.74V , V_0=0.16 , V_0=0V The threshold frequency and work function for the material.

A photon of frequency v causes photo electric emission from a surface with threshold frequency v_(0) . The de-Broglies wavelength (lambda) of the photo electron emitted is given by: