Question

When light falls on a metal surface, the maximum kinetic energy of the emitted photo-electrons depends upon(a) The time for which light falls on the metal(b) Frequency of the incident light(c) Intensity of the incident light(d) Velocity of the incident light

Answer 1

(d) Velocity of the incident light

Answer 2

K.E ( kinetic energy ) = h ( f - f₀ ) 

           h ----- > plank's constant

           f₀ ------> Threshold frequency

           f --------> Frequency 

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         h = 6.626 × 10⁻³⁴

         f₀ = 7× 10¹⁴ Hz

         f = 1 × 10¹⁵ Hz

K.E = (6.626 ×10⁻³⁴ ) ₓ [ (1 × 10¹⁵)  - (7× 10¹⁴)]

      = 1.987 × 10⁻¹⁹ J //