The force on a current carrying conducter is F=BIL sin@ . One book tells me that you do this because you need to find the component of I at 90 degrees to B. Yet another says you need to find the component of L at 90 degrees to B. Obviously you dont work out BxIsin@xLsin@, so you dont work out both components. So I was wondering, are you really just working out the component of the quantity IxL that is at right angles to B?