Direction of Magnetic Force on a Moving Charge?

[Peter G.]

Hi,

So, applying the left hand rule I got a force into the page for the question attached. The markscheme, however, claims it is out of the paper.

Can anyone help me understand why?

Thanks!

 

[rock.freak667]

If I remember correctly, the convention for flow of current would be the direction in which a positive charge would travel if placed at that point. So the field would be to the left and the current would be downwards leading to the force being into the paper.

 

[Peter G.]

Yea, that's what I thought too! They must have forgotten they put an electron there...