Exam 29: Electromagnetic Induction

A closed loop conductor that forms a circle with a radius of is located in a uniform but changing magnetic field.If the maximum emf induced in the loop is what is the maximum rate at which the magnetic field strength is changing if the magnetic field is oriented perpendicular to the plane in which the loop lies?

In the figure,a C-shaped conductor is in a uniform magnetic field B,which is increasing.The polarity of the induced emf in terminals X and Y is

A 50-cm wire placed in an east-west direction is moved horizontally to the north with a speed of 2.0 m/s.The horizontal component of the earth's magnetic field at that location is 25 μT toward the north and the vertical component is 50μT downward.What is the emf induced between the ends of the wire?

A coil of 160 turns and area 0.20 m² is placed with its axis parallel to a magnetic field of initial magnitude 0.40 T.The magnetic field changes uniformly from 0.40 T in the +x direction to 0.40 T in the -x direction in 2.0 s.If the resistance of the coil is 16 Ω,at what rate is power generated in the coil?

A 2.0-m long conducting wire is formed into a square and placed in the horizontal A uniform magnetic field is oriented above the horizontal with a strength of What is the magnetic flux through the square?

For a long ideal solenoid having a circular cross-section,the magnetic field strength within the solenoid is given by the equation B(t)= 5.0t T,where t is time in seconds.If the induced electric field outside the solenoid is 1.1 V/m at a distance of 2.0 m from the axis of the solenoid,find the radius of the solenoid.

A conducting bar slides without friction on two parallel horizontal rails that are 50 cm apart and connected by a wire at one end.The resistance of the bar and the rails is constant and equal to 0.10 Ω.A uniform magnetic field is perpendicular to the plane of the rails.A 0.080-N force parallel to the rails is required to keep the bar moving at a constant speed of 0.50 m/s.What is the magnitude of the magnetic field?

A circular metal ring is situated above a long straight wire,as shown in the figure.The straight wire has a current flowing to the right,and the current is increasing in time at a constant rate.Which statement is true?

A coil lies flat on a tabletop in a region where the magnetic field vector points straight up.The magnetic field vanishes suddenly.When viewed from above,what is the direction of the induced current in this coil as the field fades?

In the figure,a straight wire carries a steady current I perpendicular to the plane of the page.A bar is in contact with a pair of circular rails,and rotates about the straight wire.The direction of the induced current through the resistor R is

The figure shows three metal coils labeled A,B,and C heading towards a region where a uniform static magnetic field exists.The coils move with the same constant velocity and all have the same resistance.Their relative sizes are indicated by the background grid.As they enter the magnetic field the coils will have an induced electric current in them.For which coil will the current be the greatest?

As shown in the figure,a wire and a 10-Ω resistor are used to form a circuit in the shape of a square,20 cm by 20 cm.A uniform but nonsteady magnetic field is directed into the plane of the circuit.The magnitude of the magnetic field is decreased from 1.50 T to 0.50 T in a time interval of 63 ms.The average induced current and its direction through the resistor,in this time interval,are closest to

Wire is wound on a square frame,30 cm by 30 cm,to form a coil of 7 turns.The frame is mounted on a horizontal shaft through its center (perpendicular to the plane of the diagram),as shown in the figure.The coil is in clockwise rotation,with a period of 0.060 s.A uniform,horizontal,magnetic field of magnitude 0.40 T is present.At a given instant,the plane of the coil forms a 60° angle with the horizontal,as shown.At that instant,what is the magnitude of the emf induced in the coil?

A circular coil of radius 5.0 cm and resistance 0.20 Ω is placed in a uniform magnetic field perpendicular to the plane of the coil.The magnitude of the field changes with time according to B = 0.50e^-20t T.What is the magnitude of the current induced in the coil at the time ?

A rectangular coil having N turns and measuring 15 cm by 25 cm is rotating in a uniform 1.6-T magnetic field with a frequency of 75 Hz.The rotation axis is perpendicular to the direction of the field.If the coil develops a sinusoidal emf of maximum value 56.9 V,what is the value of N?

A circular loop of radius 0.10 m is rotating in a uniform external magnetic field of 0.20 T.Find the magnetic flux through the loop due to the external field when the plane of the loop and the magnetic field vector are (a)parallel. (b)perpendicular. (c)at an angle of 30° with each other.

A closed,circular loop has a counter-clockwise current flowing through it as viewed by a person on the right,as shown in the figure.If a second closed circular loop with the same radius approaches this loop with constant velocity along a common axis as shown,in what direction will a current flow in the approaching loop as viewed by the person on the right?

In the figure,two solenoids are side by side.The switch S,initially open,is closed.The induced current through the resistor R is

Suppose that you wish to construct a simple ac generator having an output of 12 V maximum when rotated at 60 Hz.A uniform magnetic field of 0.050 T is available.If the area of the rotating coil is 100 cm²,how many turns do you need?