Exam 30: Induction and Inductance

A merry-go-round has an area of 300 m² and spins at 2 rpm about a vertical axis at a place where the Earth's magnetic field is vertical and has a magnitude of 5 *10^-5 T. The emf around the rim is:

In the circuit shown, there will be a non-zero reading in galvanometer G:

A rod of length L and electrical resistance R moves through a constant uniform magnetic field perpendicular to the rod. The force that must be applied by a person to keep the rod moving with constant velocity is:

A magnet moves inside a coil. Consider the following factors: Which can affect the emf induced in the coil?

A 3.5 mH inductor and a 4.5 mH inductor are connected in parallel. When the total emf of the combination is 16 V, the rate of change of the current in the larger inductor is:

A 10-turn ideal solenoid has an inductance of 3.5 mH. When the solenoid carries a current of 2.0 A the magnetic flux through each turn is:

A rod lies across frictionless rails in a uniform magnetic field B, as shown. The rod moves to the right with speed v. In order for the emf around the circuit to be zero, the magnitude of the magnetic field should:

The quantity (B²/ $\mu$ _o) has units of:

If both the resistance and the inductance in an LR series circuit are doubled the new inductive time constant will be:

At any instant of time the total magnetic flux through a stationary conducting loop is less in magnitude than the flux associated with an externally applied field. This might occur because:

As a loop of wire with a resistance of 10 $\Omega$ moves in a non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5 mJ/s. The induced emf in the loop:

A 0.20-cm radius cylinder, 3.0 cm long, is wrapped with wire to form an inductor. At the instant the magnetic field in the interior is 5.0 mT the energy stored in the field is:

A square loop of wire moves with a constant speed v from a field-free region into a region of uniform B field, as shown. Which of the five graphs correctly shows the induced current i in the loop as a function of time t?

The emf that appears in Faraday's law is:

1 weber is the same as:

A rectangular loop of wire has area A. It is placed perpendicular to a uniform magnetic field B and then spun around one of its sides at frequency f. The maximum induced emf is:

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries a constant current i, as shown. While the wire is being moved toward the rectangle the current in the rectangle is:

A 3.5 mH inductor and a 4.5 mH inductor are connected in parallel. The equivalent inductance is:

The diagrams show three circuits with identical batteries, identical inductors, and identical resistors. Rank them according to the current through the battery just after the switch is closed, from least to greatest.

The emf developed in a coil X due to the current in a neighboring coil Y is proportional to the: