# Who's up for a challenge? Quantum Que

1. Apr 8, 2008

### minimax

1. The problem statement, all variables and given/known data
An incident x-ray has a wavelength of 0.525nm and scatters as 112 degrees above the incidental x-axis in the positive x-direction. Find the direction of propagation of the electron that the incidental wavelength hits. (the answer is to be 34 degrees below the x-axis)

2. Relevant equations
Using Compton's Effect
$$\frac{h}{\lambda_{1}}$$=$$\frac{h}{\lambda_{2}}$$ cos$$\theta$$+pecos$$\phi$$

0=$$\frac{h}{\lambda_{2}}$$ sin$$\theta$$+pesin$$\phi$$

where $$\phi$$ = angle of electron direction
$$\theta$$= angle of x-ray direction
pe=momentum of electron

3. The attempt at a solution
Since the electron momentum is not given, numbers can't be plugged in to find the angle.
Possibly the two equations have to be manipulated together (ie add/subtract) somehow?
Or using energy equations?