Physics anyone good???

Question

can someone help me solve this?

1. the energy S carried by electromagnetic waves in space is proportional to the product of two vectors E and B, where E and B represent the instantaneous values of the electric and magnetic fields. in this case the energy S is a vector, its direction being that in which the energy is flowing. must we take the dot or the cross product of E and B in order to find S?

a. the dot product

b. the cross product

c. the info given is not sufficient to determine which product is required.

thanks! 10 points for the best answer.

Answer 1

it is the cross product.

the E and B are perpendicular to the direction of the wave. Check Maxwell's equations in wikipedia or whatever.

Answer 2

it shud b either a or c........

coz cross product of two vectors is equal to a vector perpendicular to both of them...so it just cant b

Answer 3

A.the dot production