Question

Electrons with a kinetic energy of 6.023 x 10^4 J/mol
are evolved from a surface of a metal, when it is
exposed to radiation of wavelength 600 nm. The
minimum amount of energy required to remove an
electron from the metal atom is​

Answer 1

kinetic energy of one mole of electrons is given , 6.023 × 10⁴ J

we know, 1 mol of electrons = 6.023 × 10²³ electrons.

so, kinetic energy of each electron, E = 6.023 × 10⁴/6.023 × 10²³ J

= 1 × 10^-19 J

wavelength of exposed radiation, λ = 600nm = 6 × 10^-7 m

so, energy of exposed radiation , E' = hc/λ

here, h = 6.63 × 10^-34 Js , c = 3 × 10^8 m/s and λ = 6 × 10^-7 m

so, E' = (6.63 × 10^-34 × 3 × 10^8)/(6 × 10^-7)

= 3.315 × 10^-19 J

now amount of energy required to remove an electron from the metal atom = E' - E

= 3.315 × 10^-19 J - 1 × 10^-19 J

= 2.315 × 10^-15 J [Ans]