Exam 31: Faradays Law

A conducting rod (length = 80 cm)rotates at a constant angular rate of 15 revolutions per second about a pivot at one end.A uniform field (B = 60 mT)is directed perpendicularly to the plane of rotation.What is the magnitude of the emf induced between the ends of the rod?

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates about an axis through its center at constant angular velocity ω.The ends,A and E,make contact with a split ring that connects to an external circuit.The current in the external circuit of resistance R has magnitude

At what frequency should a 200-turn,flat coil of cross sectional area of 300 cm² be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V?

An electric field of 4.0 μV/m is induced at a point 2.0 cm from the axis of a long solenoid (radius = 3.0 cm,800 turns/m).At what rate is the current in the solenoid changing at this instant?

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates clockwise about an axis through its center at constant angular velocity ω.While it rotates,the point(s)at highest potential is(are)

As shown below,a square loop of wire of side a moves through a uniform magnetic field of magnitude B perpendicular to the page at constant velocity Directed to the right.Which statement regarding the electric field induced in the wires is correct for the wires at the left and right sides of the loop?

A flat coil of wire consisting of 20 turns,each with an area of 50 cm²,is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 2.0 T to 6.0 T in 2.0 s.If the coil has a total resistance of 0.40 Ω,what is the magnitude of the induced current?

A rectangular loop (area = 0.15 m²)turns in a uniform magnetic field with B = 0.20 T.At an instant when the angle between the magnetic field and the normal to the plane of the loop is (π/2)rad and increasing at the rate of 0.60 rad/s,what is the magnitude of the emf induced in the loop?

A bolt of lightning strikes the ground 200 m from a 100-turn coil oriented vertically and with the plane of the coil pointing toward the lightning strike.The radius of the coil is 0.800 m and the current in the lightning bolt falls from 6.02 × 10⁶ A to zero in 10.5 μs.What is the voltage induced in the coil over this time period? [A question for future electrical engineers: is there any way to get lightning to strike repeatedly at the same point?] ​

A rectangular wire loop (length = 60 cm,width = 40 cm)lies completely within a perpendicular and uniform magnetic field of magnitude of 0.5 T.If the length of the loop starts increasing at a rate of 20 mm/s at time t = 0,while the width is decreasing at the same rate,what is the magnitude of the induced emf at time t = 4.0 s?

A square loop (length along one side = 20 cm)rotates in a constant magnetic field which has a magnitude of 2.0 T.At an instant when the angle between the field and the normal to the plane of the loop is equal to 20° and increasing at the rate of 10°/s,what is the magnitude of the induced emf in the loop?

A loop of wire (resistance = 2.0 mΩ)is positioned as shown with respect to a long wire which carries a current.If d = 1.0 cm,D = 6.0 cm,and L = 1.5 m,what current is induced in the loop at an instant when the current in the wire is increasing at a rate of 100 A/s?

Starting outside the region with the magnetic field,a single square coil of wire enters,moves across,and then leaves the region with a uniform magnetic field Perpendicular to the page so that the graph shown below represents the induced emf.The loop moves at constant velocity )As seen from above,a counterclockwise emf is regarded as positive.In which direction did the loop move over the plane of the page?

A bar magnet is dropped from above and falls through the loop of wire shown below.The north pole of the bar magnet points downward towards the page as it falls.Which statement is correct?

A rectangular coil of 100 turns measures 40.0 cm by 20.0 cm.This coil is placed next to an electromagnet which is switched on,increasing the magnetic field through the coil from zero to 0.800 T in 50.0 ms.If the resistance of the coil is 2.0 ohms,what are the induced voltage and current in the coil?

A long solenoid (radius = 3.0 cm,2 500 turns per meter)carries a current given by I = 0.30 sin(200πt)A,where t is measured in s.When t = 5.0 ms,what is the magnitude of the induced electric field at a point which is 2.0 cm from the axis of the solenoid?

In the arrangement shown,a conducting bar of negligible resistance slides along horizontal,parallel,frictionless conducting rails connected as shown to a 2.0-Ω resistor.A uniform 1.5-T magnetic field is perpendicular to the plane of the paper.If L = 60 cm,at what rate is thermal energy being generated in the resistor at the instant the speed of the bar is equal to 4.2 m/s?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed,

A long straight wire is parallel to one edge and is in the plane of a single-turn rectangular loop as shown.If the loop is moving in the plane shown so that the distance x changes at a constant rate of 20 cm/s,what is the magnitude of the emf induced in the loop at the instant x = 5.0 cm? Let I = 50 A,a = 50 cm,b = 6.0 cm.

As shown below,a square loop of wire of side a moves through a uniform magnetic field of magnitude B perpendicular to the page at constant velocity Directed to the right.Judd says that the emf induced in the loop is zero.Roger claims that it has magnitude B )Which one,if either,is correct,and why?