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Standard XII
Physics
Photons and Photoelectric Effect
Question

In about $$1916,$$ R. A. Millikan found the following stopping potential data for lithium in his photoelectric experiments:
Use these data to make a plot like Fig. 38-2 (which is for sodium)and then use the plot to find (a) the Planck constant and (b) the work function for lithium.

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Solution
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{a} Using Einstein's photo electric effect equation,
$$\dfrac{hc}{\lambda} = KE_{max} + \phi_o$$
$$\dfrac{hc}{\lambda} = eV + \phi_o$$
$$V = \dfrac{hc}{e \lambda} - \dfrac{\phi_o}{e}$$
From the graph we find, $$ h = 6.626 \times 10^{-34} J sec$$
{b} $$W$$ ( work function ) = $$\dfrac{hc}{\lambda} = 2.3 eV$$

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Q1
In about $$1916,$$ R. A. Millikan found the following stopping potential data for lithium in his photoelectric experiments:
Use these data to make a plot like Fig. 38-2 (which is for sodium)and then use the plot to find (a) the Planck constant and (b) the work function for lithium.

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Q2
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Q5
In an experiment on photoelectric effect, the stopping potential is measured for monochromatic light beams corresponding to different wavelengths. The data collected are as follows:
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View Solution