Question

A) A straight wire 0.010 m long lies in the field of several horseshoe magnets. (The horseshoe magnets are lying side by side, with their magnetic fields pointing in the same direction; see diagram `Current balance and circuit' in the lab manual.) The wire is perpendicular to the magnetic field, B. The magnitude of B is uniform along the length of the wire and has the value 0.3 T. The wire carries a current, I, of 1 A. What is the magnitude of the force exerted on the wire by the magnetic field?

B)For the wire and magnetic field in the previous question, the directions of I and B are shown in the table below as compass directions in a plane, for four different cases. For each case, enter the direction of the force F_B exerted on the wire by the magnetic field. E.g., if F_B is Up (out of the plane) for case 1, North for 2, Down (into the plane) for 3, and West for 4, enter UNDW.

	I	B	FB
1	E	N
2	N	E
3	N	W
4	E	S

Answer 1

I am doing part B here.

1) The force will be out of the paper. because using right hand rule, if we point all four fingers in the dircetion of current i.e in the east such that the thumb will point in the direction of B i.e in north direction (upward), the the direction of palm will give the direction of force. here it will be outside of the plane.

2) here the force will be inside the plane (into the plane) because as above if we put fingers in north such that thumb facing east then the palm will face inward the plane of paper.

3) here it wil be outside the plane of paper because if fingers in north direction such that thumb facing west then palm will face outward direction, giving the direction of force.

4) here it will be inside the plane because fingers in east direction provided thumb points in south then palm will face inward the plane.