#### Question

The threshold wavelength of silver is 3800Å. Calculate the maximum kinetic energy in eV of photoelectrons emitted, when ultraviolet light of wavelength 2600Å falls on it.

(Planck’s constant, h =6.63 x 1O^{-34}J.s.,

Velocity of light in air, c = 3 x 10^{8} m / s)

#### Solution

Wavelength of silver, λ_{1} = 3800 Aº

Wavelength of ultraviolet light, λ_{2} = 2600 Aº

H = 6.63 × 10^{-34} Js

Velocity of light in air, c = 3 × 10^{8} m/s

To calculate kinetic energy, K.E. = hv − hv_{º}

`"K.E."="hc"[1/lambda-1/lambda_o]`

`"K.E."=19.89xx10^-19[1/2.6-1/3.8]`

`"K.E."=(2.416xx10^-19)/(1.6xx10^-19)`

**K.E. = 1.51 eV**

**Hence, the maximum kinetic energy emitted by the photoelectron is 1.51 eV.**

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#### APPEARS IN

Solution Calculate the Maximum Kinetic Energy in Ev of Photoelectrons Emitted, When Ultraviolet Light of Wavelength 2600a Falls on It. Concept: Einstein’s Equation - Particle Nature of Light.