#### Question

If the work function of a metal is 3 eV, calculate the threshold wavelength of that metal.

(Velocity of light = 3 x 10^{8} m/s, Planck’s constant = 6.63 x 10^{–34} J.s.; 1 eV = 1.6 x 10^{–19} J)

#### Solution

Given: W0 = 3eV = 3 x1.6 x 10^{-19}

= 4.8 x 10^{-19} J,

h = 6.63x 10^{-34} J – s,

e = 1.6 x 10^{-19} C,

c = 3 x 10^{8} m/s,

To find: Threshold wavelength (λ_{0}),

`lambda_0=(hc)/W_0`

`=(6.63xx10^-34xx3xx10^8)/(4.8xx10^-19)`

`lambda_0=4.14 xx 10^-7 m`

Threshold wavelength of the metal is 4.14 x 10^{–7} m.

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#### APPEARS IN

Solution If the Work Function of a Metal is 3 Ev, Calculate the Threshold Wavelength of that Metal. Concept: Particle Nature of Light.