Exam 30: Induction and Inductance

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:

An inductor with inductance L and a resistor with resistance R are wired in series to an ideal battery with emf . A switch in the circuit is closed at time t = 0, at which time the current is zero. A long time after the switch is thrown the potential differences across the inductor and resistor are:

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:

The diagram shows a circular loop of wire that rotates at a steady rate about a diameter O that is perpendicular to a uniform magnetic field. The maximum induced emf occurs when the point X on the loop passes:

In the experiment shown:

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

A 3.5 mH inductor and a 4.5 mH inductor are connected in series and a time varying current is established in them. When the total emf of the combination is 16 V, the emf of the larger inductor 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 emf of the inductor is given by:

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 square loop of wire lies in the plane of the page. A decreasing magnetic field is directed into the page. The induced current in the loop is:

A copper penny slides on a horizontal frictionless table. There is a square region of constant uniform magnetic field perpendicular to the table, as shown. Which graph correctly shows the speed v of the penny as a function of time t?

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries an increasing current in the direction shown. The current in the loop is:

When the switch S in the circuit shown is closed, the time constant for the growth of current in R₂ 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 loop, the current in the loop is:

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:

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

An inductance L and a resistance R are connected 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 rate of increase of the energy stored in the inductor is a maximum:

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?

A cylindrical region of radius R contains a uniform magnetic field, parallel to its axis, with magnitude that is changing linearly with time. If r is the radial distance from the cylinder axis, the magnitude of the induced electric field inside the cylindrical region is proportional to:

Immediately after switch S in the circuit shown is closed, the current through the battery is: