A circular loop of flexible iron wire has an initial circumference of, but its circumference is decreasing at a constant rate of due to a tangential pull on the wire. The loop is in a constant, uniform magnetic field oriented perpendicular to the plane of the loop of magnitude 1.Find the emf induced in the loop, at the instant when have passed. 2.Find the direction of the induced current in the loop, as viewed looking along the direction of the magnetic field inside the loop Clockwise or counterclockwise?

A single-turn circular loop of wire of radius 50 mm lies in a plane perpendicular to a spatially uniform magnetic field. During a 0.10-s time interval, the magnitude of the field Increases uniformly from 200 to 300 mT. (a) Determine the emf Induced in the ioop. (b) If the magnetic field is directed out of the page, what is the direction of the cun-ent induced in the loop?

The accompanying figure shows a metal disk of inner radius r1 and other radius r2 rotating at an angular velocity while in a uniform magnetic field directed parallel to the rotational axis. The brush leads of voltmeter are connected to the dark's inner and outer surfaces as shown. What is the reading of the voltmeter ?

The circular conducting loops shown in the accompanying figure are parallel, perpendicular to the plane of the page, and coaxial. (a) When the switch S is dosed, what is the direction of the cun’ent induced in D? (b) When the switch is opened, what is the direction of the current induced in loop D?

A circular loop of wire of radius 10 cm. is mounted on a vertical shaft and rotated at a frequency of 5 cycles per second in a region of uniform magnetic field of 2104T perpendicular to the arcs of rotation, (a) Find an Expression for the time-dependent flux through the ring (b) Determine die time-dependent current through the ring if it has a resistance of 10.

A rectangular copper ring, of mass 100 g and resistance 0.2 1, is in a region of uniform magnetic field that is perpendicular to the area enclosed by the ring and horizontal to Earth’s surface. The ring is let go from rest when it is at the edge of the nonzero magnetic field region (see below). (a) Find its speed when the ring just exits the region of uniform magnetic field. (b) If it was let go at t = 0, what is the time when it exits the region of magnetic field for the following values: a=25cm,b=50cmB=3T , and g=9.8m/s2 ? Assume the magnetic field of the induced current is negligible compared to 3T.

Check Your Understanding (a) What is the magnetic flux through one turn of a solenoid of self- inductance 8.0 × 10-5 H when a current of 3.0 A flows through it? Assume that the solenoid has 1000 turns and is wound from wire of diameter 1.0 mm. (b) What is the cross-sectional area of the solenoid?

The armature and field coils of a series-wound motor have a total resistance of 3.0 . When connected to a 120-V source and running at normal speed, the motor draws 4.0 A. (a) How large is tire back emf? (b) What current will the motor draw just after it is turned on? Can you suggest a way to avoid this large initial current?

Use Lenz’s law to determine tl direction of induced current in each case.

In the circuit shown in the accompanying figure, the rod slides along the conducting rails at a constant velocity v. The velocity is in the same plane as the rails and directed at an angle 0 to them. A uniform magnetic field B is directed out of the page. What is the emf induced in the rod? To