Question

If the threshold wavelength for a metal is 6200 Å
then minimum energy required to eject an electron
from the surface of metal is (nearly)
(1) 1 eV
(2) 2 eV
(3) 0.5 eV
(4) 0.8 eV​

Answer 1

Answer:

b

Explanation:

applying formula

E=hc/lemda

Answer 2

Answer:

The minimum energy required to eject an electron from the surface of the metal is 2eV i.e.option(2).

Explanation:

The energy of the metal in electron-volt is given as,

$E=\frac{12400}{\lambda}$      (1)

Where,

E=energy of the metal in electron-volt

λ=wavelength of the metal in A°

From the question we have,

The wavelength of the metal(λ)=6200A°

By substituting the value of "λ" in equation (1) we get;

$E=\frac{12400}{6200}$

$E=2eV$

Hence, the minimum energy required to eject an electron from the surface of the metal is 2eV i.e.option(2).