Exercise 1

Protons move in a circle of radius 6.30cmin a0.460-Tmagnetic field.What value of electric field could make their paths straight? Exercise 2

If an electric wire is allowed to produce a magnetic field no larger than that of the Earth(0.50104T)at a distance of 12cmfrom the wire, what is the maximum current the wire can carry? (answer to two significant figures and include the appropriate units)

Exercise 3

A horizontal compass is placed14cmdue south from a straight vertical wire carrying a45-Acurrent downward. Assume the horizontal component of the Earth's field at this point is0.4510^4Tand the magnetic declination is0. Determine the angle of the direction of the compass needle. Angle =? degrees north of west