Please answer all questions.

1			A straight wire 15 cm long, carrying a current of 6.0 A, is in a uniform field of 0.40 T. What is the force on the wire when it is (a) at right angles to the field and (b) at the 30° to the field?
			A)	(a) 36 N (b) 0.36 N
			B)	(a) 0.36 N (b) 0.31 N
			C)	(a) 2.25 N (b) 0.31 N
			D)	(a) 0 N (b) 0.72 N
2			An ion (q=+2e) enters a magnetic field of 1.2 Wb/m2 at a velocity of 2.5 x 105 m/s perpendicular to the field. Determine the force on the ion.
			A)	9.6 x 10-14 N
			B)	6.0 x 105 N
			C)	0 N
			D)	6.7 x 10-14 N
3			An electron is accelerated from rest through a potential difference of 3750 V. It enters a region where B=4.0 x 10-3 T perpendicular to its velocity. Calculate the radius of the path it will follow.
			A)	5.2 cm
			B)	5.3 x 10-6 m
			C)	1.8 x 108 m
			D)	1.4 x 10-9 m
4			An electron is accelerated from rest through a potential difference of 800 V. It then moves perpendicularily to a magnetic field of 30 G. Find the radius of its orbit and its orbital frequency.
			A)	(a) 3.0 x 10-6 m, (b) 1.2 x 10-8 Hz
			B)	(a) 2.9 x 10-7 m, (b) 0.84 Hz
			C)	(a) 3.2 cm, (b) 84 MHz
			D)	(a) 3.2 x 106 m, (b) 2.7 x 10-15 Hz
5			Two long parallel wires are 4 cm apart and carry currents of 2 A and 6 A in the same direction. Compute the force between the wires per meter of wire length.
			A)	6.0 x 10-7 N/m, attraction
			B)	6.0 x 10-5 N/m, attraction
			C)	1.0 x 10-5 T, attraction
			D)	6.0 x 10-5 N/m, repulsion
6			Two long fixed parallel wires, A and B, are 10 cm apart in air and carry 40 A and 20 A respectively, in opposite directions. Determine the resultant field (a) on a line midway between the wires and parallel to them and (b) on a line 8.0 cm from wire A and 18 cm from wire B (c) What is the force per meter on a third long wire, midway between A and B and in their plane, when it carries a current of 5.0 A in the same direction as the current in A.
			A)	(a) 8.0 x 10-5 T (b) 1.2 x 10-4 T (c) 1.2 x 10-3 N/m, toward B
			B)	(a) 2.4 x 10-4 T (b) 7.8 x 10-5 T (c) 1.2 x 10-3 N/m, toward A
			C)	(a) 2.4 x 10-6 T (b) 7.8 x 10-7 T (c) 0
			D)	(a) 1.2 x 10-4 T (b) 5.6 x 10-6 T (c) 2.1 x 104 N/m, toward A
7			An ideal solenoid 50 cm long has 4000 loops wound on it. Compute B in its interior when a current of 0.25 A exists in the winding.
			A)	10.0 mT
			B)	2.5 mT
			C)	2.5 x 10-5 T
			D)	0.63 mT
8			A certain electromagnet consists of a solenoid (5.0 cm long with 200 loops) wound on a soft-iron core that intensifies the field 130 times. (We say that the relative permeability of the iron is 130.) Find B within the iron when the current in the solenoid is 0.30 A.
			A)	4.9 x 10-5 T
			B)	0.20 T
			C)	2.0 mT
			D)	1.2 x 10-5 T
9			An electron is traveling horizontally east at the equator. What is the direction of the magnetic force on the particle?
			A)	Up
			B)	Down
			C)	West
			D)	Zero