CAPE Physics Unit 2 · 2014 · Paper 1 · Question Q31

An atom makes a transition from an energy state, E_2, to a lower energy state, E_1. Which of the following expressions gives the frequency of radiation emitted in terms of Planck's constant, h?

1. (A)\frac{1}{h(E_2 - E_1)}
2. (B)\frac{E_1 - E_2}{h}
3. (C)\frac{E_2 - E_1}{h}
4. (D)\frac{h}{E_2 - E_1}