The current in a wire points due east, and the force (due to a magnetic field) on the wire is down. If the force on the wire is at a maximum, in which direction does the magnetic field point?  

Two naturally occurring opiates derived from the poppy plant are:

An AC generator has a frequency of 500 Hz, armature area 35 cm2 and the wire is wrapped around the armature 80 times. The AC generator is hooked up to a transformer with 20 primary coils and 100 secondary coils, and the output of the secondary coil is 100 V rms. What is the magnetic field of the generator?

The right portion of a rectangular loop is in a constant magnetic field into the page, while on the left there is no magnetic field, as shown in the figure. If the loop is moving right, in which direction will there be a net force on the loop?

An electron is moving

What will happen if the frequency of the armature’s rotation is increased in an AC generator?  

If, using the same diagram as the previous problem, the loop is stationary but a battery causes a clockwise current in the loop, in which direction is the net force on the loop?

A 0.002 C charge is in a 0.5 T magnetic field which points in the positive y-direction.  If the force on the charge is

A 120 V AC voltage needs to be decreased to 30 V with a transformer. If the primary coil of the transformer has 80 turns, how many turns should the secondary coil have?  

A power line has a current which runs due east. In which direction does the magnetic field point at a location directly above the power line?