The stopping potential in a photoelectric experiment is linearly related to the inverse of the wavelength (1/λ) of the light falling on the cathode. The potential difference inverse of the cut-off wavelength (1/λ) of the X-ray emitted. Show that the slopes of the lines in the two cases are equal and find its value.

Given:


Stopping potential is proportional to inverse of wavelength (1/λ)


let Vo be the stopping potential


v1 and λ1 be the operating frequency and voltage of the x-ray tube
v2 and λ2be the cut- off frequency and voltage of the x-ray tube

since ,


and




in the above equations, slopes are the same


V0λ2=Vλ1




Value of the slope= 1.242×10-6 Vm


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