1. Suppose a straight 1.00 - mm -diameter copper wire could just "float" horizontally in air because of the force due to the Earth's magnetic field B, which is hotisontal, perpendicular to the wire, and of magnitude 5.0 x 10-T. What current would the wire carry? Does the answer seem feasiable? 2. Alpha particles of charge q = +2e and mass m = 6.6 x 10-27kg are emitted from a radiactive source at a speed of 1.6 x 101m/s. What magnetic field strength would be required to bend them into a circular path of radius r = 0.25m ? 3. A doubly charged helium atom (q = +2e) whose mass is m = 6.6 x 10-27kg is accelerated by a voltage of 2100V. a) What will be its radius of curvature if it moves in a plane perpendicular to a uniform 0.340 - T field? b) What is its period of revolution? 4. Determine the magnetic field midway between two long straight wires 2.0cm apart in terms of the current I in one when the other carries 15A. Assume these currents are a) in the same direction, and b) in opposite directions. 5. A long horizontal wire carries a current of 48A. A second wire, made of 2.5 - mm -diameter copper wire and parallel to the first, is kept in suspension magnetically 15cm below. Determine the magnitude and direction of the current in the lower wire. 1 = 48 A 15 cm 1 =