Platinum, which is widely used as a catalyst, has a work function $\Phi$ (the minimum energy needed to eject an electron from the metal surface) of 9.05 × 10^-19 J. What is the longest wavelength of light which will cause electrons to be emitted? A) 2.196 × 10^-7 m B) 4.553 × 10^-6 m C) 5.654 × 10² m D) 1.370 × 10¹⁵ m E) 10⁶ m

Question

Platinum, which is widely used as a catalyst, has a work function $\Phi$ (the minimum energy needed to eject an electron from the metal surface) of 9.05 × 10^-19 J. What is the longest wavelength of light which will cause electrons to be emitted? A) 2.196 × 10^-7 m B) 4.553 × 10^-6 m C) 5.654 × 10² m D) 1.370 × 10¹⁵ m E) > 10⁶ m

Quizplus · Accepted Answer

The longest wavelength corresponds to the minimum energy needed to eject an electron, which is given by the work function. Using the equation λ = hc/ϕ, where h is Planck's constant (6.626 × 10^-34 J·s) and c is the speed of light (3.00 × 10^8 m/s), we find λ = (6.626 × 10^-34 J·s * 3.00 × 10^8 m/s) / 9.05 × 10^-19 J = 2.196 × 10^-7 m.

Platinum, Which Is Widely Used as a Catalyst, Has a Work