Light of wavelength λ = 400 nm is incident on a photosensitive metal whose work function is 2 eV. The maximum kinetic energy of photo electrons emitted will be

Question

Light of wavelength λ = 400 nm is incident on a photosensitive metal whose work function is 2 eV. The maximum kinetic energy of photo electrons emitted will be (A)  2.2 eV (B)  1.1 eV (C)  1.5 eV (D)  3 eV

Tardigrade Admin · Accepted Answer

According to Einstein's photoelectric equation, K = (hc/λ) - φ Here, λ = 400 nm , hc = 1242 eV - nm φ = 2 eV ∴ K = (1242 eV -nm/400 nm) - 2eV = 3.1 eV - 2 eV = 1.1 eV

Q. Light of wavelength $λ = 400 nm$ is incident on a photosensitive metal whose work function is $2 e V$ . The maximum kinetic energy of photo electrons emitted will be

$2.2 e V$

$1.1 e V$

$1.5 e V$

$3 e V$

According to Einstein's photoelectric equation, $K = \frac{h c}{λ} - ϕ$
Here, $λ = 400 nm, h c = 1242 e V - nm$
$ϕ = 2 e V$
$∴ K = \frac{1242 e V - nm}{400 nm} - 2 e V$
$= 3.1 e V - 2 e V = 1.1 e V$

Q. Light of wavelength λ=400nm is incident on a photosensitive metal whose work function is 2eV. The maximum kinetic energy of photo electrons emitted will be

2.2eV

1.1eV

1.5eV

3eV