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 lowest energy photon that can eject an electron. Using the equation $ \lambda = \frac{hc}{\phi} $, where $ h $ is Planck's constant and $ c $ is the speed of light, we find the wavelength to be approximately 2.196 * 10¯⁷ m.

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