1-Derive an expression for 21, the wavelength of light emitted by a particle in a rigid box during a quantum jump from n =2 to n =1

.

Express your answer in terms of the particle mass m

, the box length L, the Plank's constant h, and the speed of light c.

2-In what length rigid box will an electron undergoing a 21 transition emit light with a wavelength of 717 nm

?

Express your answer with the appropriate units.