Light of wavelength λA and λB falls on two identical metal plates A and B respectively. The maximum kinetic energy of photoelectrons is KA and KB respectively, then which one of the following relations is true? (λA=2 λB)

Question

Light of wavelength λA and λB falls on two identical metal plates A and B respectively. The maximum kinetic energy of photoelectrons is KA and KB respectively, then which one of the following relations is true? (λA=2 λB) (A) KA<(KB/2) (B) 2 KA=KB (C) KA=2 KB (D) KA>2 KB

Tardigrade Admin · Accepted Answer

According to Einstein photoelectric equation, KA=(h c/λA)-φ ⇒ 2 KA=(2 h c/λA)-2 φ or 2 KA+φ=(2 h c/λA)-φ Given λA=2 λB λ B =λ A / 2 KB=(2 h c/λA)-φ ⇒ 2 KA+φ=KB ⇒ KA<(KB/2)

Q. Light of wavelength $λ_{A}$ and $λ_{B}$ falls on two identical metal plates $A$ and $B$ respectively. The maximum kinetic energy of photoelectrons is $K_{A}$ and $K_{B}$ respectively, then which one of the following relations is true? $(λ_{A} = 2 λ_{B})$

$K_{A} < \frac{K _{B}}{2}$

$2 K_{A} = K_{B}$

$K_{A} = 2 K_{B}$

$K_{A} > 2 K_{B}$

Q. Light of wavelength λA​ and λB​ falls on two identical metal plates A and B respectively. The maximum kinetic energy of photoelectrons is KA​ and KB​ respectively, then which one of the following relations is true? (λA​=2λB​)

KA​<2KB​​

2KA​=KB​

KA​=2KB​

KA​>2KB​

According to Einstein photoelectric equation, KA​=λA​hc​−ϕ ⇒2KA​=λA​2hc​−2ϕ or 2KA​+ϕ=λA​2hc​−ϕ Given λA​=2λB​ λB​=λA​/2 KB​=λA​2hc​−ϕ ⇒2KA​+ϕ=KB​ ⇒KA​<2KB​​

Q. Light of wavelength $λ_{A}$ and $λ_{B}$ falls on two identical metal plates $A$ and $B$ respectively. The maximum kinetic energy of photoelectrons is $K_{A}$ and $K_{B}$ respectively, then which one of the following relations is true? $(λ_{A} = 2 λ_{B})$

$K_{A} < \frac{K _{B}}{2}$

$2 K_{A} = K_{B}$

$K_{A} = 2 K_{B}$

$K_{A} > 2 K_{B}$