Exam 30: Induction and Inductance

The graph shows the magnitude B of a uniform magnetic field that is perpendicular to the plane of a conducting loop.Rank the four regions indicated on the graph according to the magnitude of the emf induced in the loop, from least to greatest.

A circular loop of wire is positioned half in and half out of a square region of constant uniform magnetic field directed into the page, as shown.To induce a clockwise current in this loop:

A rod with resistance R lies across frictionless conducting rails in a constant uniform magnetic field B, as shown.Assume the rails have negligible resistance.The magnitude of the force that must be applied by a person to pull the rod to the right at constant speed v is:

An 8.0-mH inductor and a 2.0- $\Omega$ resistor are wired in series to a 20-V ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.After a long time the current in the resistor and the current in the inductor are:

An electric field is associated with every:

A copper hoop is held in a vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction.The largest induced emf is produced when the hoop is:

An 8.0-mH inductor and a 2.0- $\Omega$ resistor are wired in series to an ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.The current reaches half its final value at a time of:

Coils P and Q each have a large number of turns of insulated wire.When switch S is closed, the pointer of galvanometer G is deflected toward the left.Now that S is closed, to make the pointer of G deflect toward the right one could:

You push a permanent magnet with its north pole away from you toward a loop of conducting wire in front of you.Before the north pole enters the loop the current in the loop is:

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

A 6.0-mH inductor and a 3.0- $\Omega$ resistor are wired in series to a 12-V ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.2.0 ms later the energy stored in the inductor is:

A 6.0 mH inductor is in a circuit.At the instant the current is 5.0 A and its rate of change is 200 A/s, the rate with which the energy stored in the inductor is increasing is:

A 2.0 T uniform magnetic field makes an angle of 30 $\degree$ with the z axis.The magnetic flux through a 3.0 m² portion of the xy plane is:

An inductance L, resistance R, and ideal battery of emf are wired in series.A switch in the circuit is closed at time t = 0, at which time the current is zero.At any later time t the potential difference across the resistor is given by:

A circular loop of wire rotates about a diameter in a magnetic field that is perpendicular to the axis of rotation.Looking in the direction of the field at the loop the induced current is:

As an externally generated magnetic field through a certain conducting loop increases in magnitude, the field produced at points inside the loop by the current induced in the loop must be:

An inductance L, resistance R, and ideal battery of emf are wired in series and the circuit is allowed to come to equilibrium.A switch in the circuit is opened at time t = 0, at which time the current is /R.At any later time t the current i is given by:

A long narrow solenoid has length ℓ and a total of N turns, each of which has cross-sectional area A.Its inductance is:

An 8.0-mH inductor and a 2.0- $\Omega$ resistor are wired in series to a 20-V ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.Immediately after the switch is thrown the potential differences across the inductor and resistor are:

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