Rutherford Scattering model geometry

[thegirl]

Hi,

I was just wondering if someone could help clarify how pi - theta = phi?



That is the link to the youtube video I was watching, the guys pretty good check him out if you want to learn how to derive the differential scattering cross section.

 

[Jonathan Yang]

He is just looking at the case when phi + theta = pi radians

 

[thegirl]

Thank You

When would that be? when the scattering angle is really big?