A certain metallic surface is illuminated by monochromatic radiation of wavelength . The stopping potential for photoelectric current for this radiation is . If the same surface is illuminated with a radiation of wavelength , the stopping potential is . T

Question

A certain metallic surface is illuminated by monochromatic radiation of wavelength $λ$ . The stopping potential for photoelectric current for this radiation is $3 V_{0}$ . If the same surface is illuminated with a radiation of wavelength $2 λ$ , the stopping potential is $V_{0}$ . The threshold wavelength of this surface for photoelectric effect is _____ $λ$ .

Smart Achievers · Accepted Answer

(4)

$K E = \frac{h c}{λ} - ϕ .....(i)$

$λ$

$e V_{0} = \frac{h c}{2 λ_{0}} - ϕ .....(ii)$

$Using (i) & (ii) ϕ = \frac{h c}{4 λ_{0}} = \frac{h c}{λ_{t}}$

$λ_{t} = 4 λ_{0}$

Solution

Ans.
(4)

$K E = \frac{h c}{λ} - ϕ .....(i)$

$e (3 V_{0}) = \frac{h c}{λ_{0}} - ϕ .....(i)$

$e V_{0} = \frac{h c}{2 λ_{0}} - ϕ .....(ii)$

$Using (i) & (ii) ϕ = \frac{h c}{4 λ_{0}} = \frac{h c}{λ_{t}}$

$λ_{t} = 4 λ_{0}$

Want Us to Email you About Special Offers & Updates?

Solution

Ans. (4) KE=hcλ-ϕ .....(i) e(3V0)=hcλ0-ϕ .....(i) eV0=hc2λ0-ϕ .....(ii) Using (i) & (ii) ϕ=hc4λ0=hcλt λt=4λ0

Want Us to Email you About Special Offers & Updates?

Ans.
(4)

$K E = \frac{h c}{λ} - ϕ .....(i)$

$e (3 V_{0}) = \frac{h c}{λ_{0}} - ϕ .....(i)$

$e V_{0} = \frac{h c}{2 λ_{0}} - ϕ .....(ii)$

$Using (i) & (ii) ϕ = \frac{h c}{4 λ_{0}} = \frac{h c}{λ_{t}}$

$λ_{t} = 4 λ_{0}$