determine the longest wavelength of light required to remove an electron from a sample of potassium metal, if the binding energy for an electron in K is 1,76x10*3 kj/mol.

The wavelength of light is 68 nm.

Explanation:

Given dа ta:

Binding energy of electron = 176 * 10³ Kj / mol or (1.76 * 10⁶ j/mol)

Wavelength of light require to remove the electron = ?

Solution:

E = hc / λ

h = planck constant (6.63*10⁻³⁴ J/s)

c = speed of light = (3*10⁸ m/s)

The energy require per electron is

1.76 * 10⁶ j / 6.02 * 10²³ = 2.92 * 10⁻¹⁸ J

Now we will put the values in formula,

E = hc / λ

λ = hc / E

λ = 6.63*10⁻³⁴ m². kg. s⁻¹. 3*10⁸ m/s / 2.92 * 10⁻¹⁸ J

λ = 19.89*10⁻²⁶ m / 2.92 * 10⁻¹⁸ (m². kg. s⁻² = J)

λ = 6.8 * 10⁻⁸ m

λ = 6.8 * 10⁻⁸ * 10⁹

λ = 68 nm