Question

To make an electric motor, you create a circular loop of wire with radius 0.0100 m. You also have a magnet that can produce a relatively uniform magnetic field of strength 0.30 T 2. a. At a certain point, the magnetic flux through the loop is 2.00 x 10- T.m2; what is the angle between the plane of the loop and the field? (Note: the angle is zero if the loop is oriented like figure P27.21 in Practice, p. 495.) b. What is the minimum flux through the loop? c. What is the maximum flux through the loop? Two wires lie in the xy-plane and cross at the origin (x, y)-(0,0). One carries a current 1 in the +y φ direction, and one carries the same current I in the +x (?) direction. What are the directions of the magnetic field at these four points: (x, y) = (1, 1), ( 1,-1), (-1, 1), and (-1,-1)? 3. A loop of wire at the origin of the xy-plane carries a current that circulates in the clockwise direction when viewed from "above" (from the positive z-axis). 4. a. b. c. d. e. Determine the direction of the magnetic field at the origin. Determine the direction of the magnetic field at a point (r,0), outside the loop Determine the direction of the magnetic field at a point (O.y), outside the loop. Determine the direction of the magnetic dipole moment of the loop. This loop experiences a clockwise torque when viewed looking down the negative y axis toward the origin. If the torque is due to an external magnetic field that points along the x-axis, what is the direction of this magnetic field, +x or-x?

Answer 1

radius, r=0.01 m

magnetic field, B=0.3T

a)

flux=B*A*cos(theta)

2*10^-5=0.3*(pi*0.01^2)*cos(theta)

==> theta=77.75 degrees

b)

minimum flux=0

c)

maximum flux=B*A*cos(theta)

=0.3*(pi*0.01^2)*cos(0)

=9.42*10^-5 T.m^2