Exam 8: Magnetic Induction

A loop rests in the xy plane. The z axis is normal to the plane and positive upward. The direction of the changing flux is indicated by the arrow on the z axis. The diagram that correctly shows the direction of the resultant induced current in the loop is

Use the following figure for the next three problems. -A rectangular coil of length l = 20 cm and width w = 15 cm is moving at a constant speed v = 5 m/s. It enters a region of uniform magnetic field B = 0.2 T from the left. While the coil is completely immersed in the field, the voltage across points a and b is

Use the following figure for the next three problems. -A rectangular coil moving at a constant speed v enters a region of uniform magnetic field from the left. While the coil is entering the field, the direction of the magnetic force is

A uniform magnetic field of 0.5 T is parallel to the y axis. A square coil of side 10 cm has 300 turns and lies in the xy plane as shown. The magnetic flux through the coil is

The current in an RL circuit is zero at time t = 0 and increases to half its final value in 6.0 s. The time constant of this circuit is approximately

A square coil of wire with side 9.0 cm and 8 turns sits in a uniform magnetic field of 2 T that is perpendicular to the plane of the coil. If an EMF of 0.5 V is induced in the coil when the magnetic field is reversed, find the time taken for the field reversal.

A circular loop, of radius 15 cm and negligible resistance, is sitting in a perpendicular magnetic field of 0.1 T. If the magnetic field strength changes to a value of 0.5 T in 0)5 s, calculate the induced current in the loop if it is in series with a 20 ohm resistor.

The magnetic flux through a 50-cm-long solenoid that has 500 turns of radius 3.0 cm is 3.0 *10^-2 Wb. Calculate the current through the solenoid.

The wire is located in a region in which there is a uniform magnetic field in the y direction. You note that the induced EMF in the wire is zero. From this observation, you can conclude that

A uniform magnetic field of 0.5 T is parallel to the z axis. A square coil of side 10 cm has 300 turns and lies in the xy plane as shown. The magnetic flux through the coil is

A square loop of sides a lies in the yz plane with one corner at the origin. A varying magnetic field where k is a constant, passes through the loop. The magnetic flux through the loop is

What is the time constant of an RL circuit with a resistance R = 25 $\Omega$ and an inductance L = 5.4 mH?

A wire rod rolls with a speed of 20 m/s on two metallic rails, 1.0 m apart, that form a closed loop. If the magnetic field is 1.5 T into the page, the power dissipated in the resistor R and the current direction are, respectively,

You can change the magnetic flux through a given surface by

Which of the following is a vector quantity?

An open switch in an RL circuit is closed at time t = 0, as shown. The curve that best illustrates the variation of current with time is

Eddy currents

A rectangular loop of wire (0.10 m by 0.20 m) carries a current of 5.0 A in a counterclockwise direction. The loop is oriented, as shown, in a uniform magnetic field of 1.5 T. The magnetic flux of is

A coil of self inductance 7.5 mH and resistance of 30 $\Omega$ is placed across the terminals of a 12-V battery of negligible internal resistance. The current in this circuit after 50 $\mu$ s is approximately

A wire rod rolls with a speed of 8.0 m/s on two metallic rails, 30 cm apart, that form a closed loop. A uniform magnetic field of magnitude 1.20 T is into the page. The magnitude and direction of the current induced in the resistor R are