Stationary particle in a laser beam

1. Mar 6, 2007

Dart82

1. The problem statement, all variables and given/known dataA stationary particle of charge q = 3.0 10-8 C is placed in a laser beam whose intensity is 2.5 103 W/m2.

(a) Determine the magnitude of the electric force exerted on the charge.

(b) Determine the magnitude of the magnetic force exerted on the charge.

2. Relevant equations
Force on a charge--> F=qE
S = cu
u = (1/2)εo*E^2

3. The attempt at a solution
a.) i am given S and i know c so i can find u by S/c = u.
now that i have u i can solve for E using u = (1/2)εo*E^2.
I multiply E times q to get F.
sounds easy enough and makes sense to me, however i am doing something wrong here huh?

b.) i know that the magnitude will be zero since the charge is stationary.

2. Mar 7, 2007

Meir Achuz

Looks OK to me.