In Fig. electromagnetic radiations of wavelength 200nm are incident on a metallic plate A. the photoelectrons are accelerated by a potential difference of 10 V. These electrons strike another metal plate B from which electromagnetic radiations are emitted. The minimum wavelength of emitted photons is 100nm. If the work function of metal A is found to be `(xxx10^-1)ev`, then find the value of x. (Given `hc=1240eV` nm)

Answer

A

Explanation

As the electron returns to ground state after emitting six different wavelength in emission spectrum, there must be a difference of `2` between the ground and excited state. Also the grounf should be `n=2`. Hence `n_(1)=4`, `n=4`
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