Question

The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium, this work function equals 4.34 × 10−19 J. What is the minimum frequency of light for the photoelectric effect in calcium?

Answer 1

Answer:

Minimum required frequency is υmin = 654.9 x 10¹² Hz

Explanation:

The energy of a photon is given by the equation:

E = hυ

where,

E = energy of photon

h = Plank's Constant = 6.626 x 10⁻³⁴ J.s

υ = frequency

The minimum energy of photon, must be equal to the work function of Calcium.

Emin = ∅₀ = h(υmin)

υmin = ∅₀/h

where,

υmin = minimum frequency

∅₀ = work function = 4.34 x 10⁻¹⁹ J

Therefore,

υmin = 4.34 x 10⁻¹⁹ J/6.625 x 10⁻³⁴ J.s

υmin = 654.9 x 10¹² Hz