Exam 30: Induction and Inductance

A car travels northward at 75 km/h along a straight road in a region where Earth's magnetic field has a vertical component of 0.50 * 10^-4 T.The emf induced between the left and right side, separated by 1.7 m, is:

One hundred turns of insulated copper wire are wrapped around an iron core of cross-sectional area 0.100 m².The circuit is completed by connecting the coil to a 10- $\Omega$ resistor.As the magnetic field along the coil axis changes from 1.00 T in one direction to 1.00 T in the other direction, the total charge that flows through the resistor is:

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:

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 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?

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

Two coils have a mutual inductance of 3.5 mH.If the current in one coil is changing at a rate of 4.8 A/s, what is the emf induced in the second coil?

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

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

A changing magnetic field pierces the interior of a circuit containing three identical resistors.Two voltmeters are connected as shown.V₁ reads 1 mV across R.V₂ reads the voltage across the other two resistors, which is:

In the experiment shown:

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:

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.

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 is:

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 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:

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:

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 flat coil of wire, having 5 turns, has an inductance L.The inductance of a similar coil having 20 turns is:

The figure shows a bar moving to the right on two conducting rails.To make an induced current i in the direction indicated, a constant magnetic field between the rails should be in what direction?