Light of wavelength λ falls on a metal having work function hc/ λ0 Photoelectric effect will take place only if

Question

Light of wavelength λ falls on a metal having work function hc/ λ0 Photoelectric effect will take place only if (A) λ ≥ λ0 (B) λ ≥ 2λ0 (C) λ ≤ λ0 (D) λ < λ0/2

Tardigrade Admin · Accepted Answer

hv = hv 0+ K . E v α (1/λ) ⇒ ( hc /λ)=( hc /λ0)+ K . E ∴ K . E =( hc /λ λ0)(λ0-λ) as K . E ≥ 0 ⇒ λ0-λ ≥ 0 ⇒ λ ≤ λ0

Q. Light of wavelength $λ$ falls on a metal having work function hc/ $λ_{0}$ Photoelectric effect will take place only if

$λ \geq λ_{0}$

$λ \geq 2 λ_{0}$

$λ \leq λ_{0}$

$λ < λ_{0} /2$

$h v = h v_{0} + K . E$
$v α \frac{1}{λ}$
$\Rightarrow \frac{h c}{λ} = \frac{h c}{λ _{0}} + K . E$
$∴ K . E = \frac{h c}{λ λ _{0}} (λ_{0} - λ)$
as $K . E \geq 0$
$\Rightarrow λ_{0} - λ \geq 0$
$\Rightarrow λ \leq λ_{0}$

Q. Light of wavelength λ falls on a metal having work function hc/ λ0​ Photoelectric effect will take place only if

λ≥λ0​

λ≥2λ0​

λ≤λ0​

λ<λ0​/2