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Dual Nature Of Radiation And Matter

Question
CBSEENPH12047827

Light of frequency v falls on material of threshold frequency vo, Maximum kinetic energy of emitted electron is proportional to 

  • ν - νo

  • ν

  • v - vo

  • vo

Solution

A.

ν - νo

When light falls on a metallic surface, ejection of photoelectron results. In this process, conservation
of energy holds.

Thus, from the  law of conservation of energy,

Energy imparted by the photon 

             = Maximum kinetic energy of the emitted electron + work function of the metal

⇒   hv = (KE)max  + ϕ

but ϕ = o  being threshold frequency.

∴          KEmax = hv - hvo

⇒          (KE)max ∝ v - vo