When a metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential is 5 V0. When the same surface is illuminated with light of wavelength 3 λ, the stopping potential is V0. The work function of the metallic surface is (h c/k λ). Find k.

Question

When a metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential is 5 V0. When the same surface is illuminated with light of wavelength 3 λ, the stopping potential is V0. The work function of the metallic surface is (h c/k λ). Find k. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

(h c/λ)=5 e V0+φ (h c/3 λ)=e V0+φ ⇒ (2 h c/3 λ)=4 e V0 ⇒ φ=(h c/6 λ)

Q. When a metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential is 5V0​. When the same surface is illuminated with light of wavelength 3λ, the stopping potential is V0​. The work function of the metallic surface is kλhc​. Find k.

λhc​=5eV0​+ϕ 3λhc​=eV0​+ϕ ⇒3λ2hc​=4eV0​ ⇒ϕ=6λhc​

$\frac{h c}{λ} = 5 e V_{0} + ϕ$
$\frac{h c}{3 λ} = e V_{0} + ϕ$
$\Rightarrow \frac{2 h c}{3 λ} = 4 e V_{0}$
$\Rightarrow ϕ = \frac{h c}{6 λ}$