Exam 31: Faradays Law

In a region of space where the magnetic field of the earth has a magnitude of 80 μT and is directed 30° below the horizontal,a 50-cm length of wire oriented horizontally along an east-west direction is moved horizontally to the south with a speed of 20 m/s.What is the magnitude of the induced potential difference between the ends of this wire?

A conducting bar of length L rotates with a constant angular speed of +2.0 rad/s about a pivot P at one end,as shown.A uniform magnetic field (magnitude = 0.20 T)is directed into the paper.If L = 0.40 m,what is the potential difference,V_A − V_P?

An AC generator consists of 6 turns of wire.Each turn has an area of 0.040 m².The loop rotates in a uniform field (B = 0.20 T)at a constant frequency of 50 Hz.What is the maximum induced emf?

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 solenoid has a radius of 4.0 cm and has 800 turns/m.If the current in the solenoid is increasing at the rate of 3.0 A/s,what is the magnitude of the induced electric field at a point 2.2 cm from the axis of the solenoid?

A conducting rod (length = 2.0 m)spins at a constant rate of 2.0 revolutions per second about an axis that is perpendicular to the rod and through its center.A uniform magnetic field (magnitude = 8.0 mT)is directed perpendicularly to the plane of rotation.What is the magnitude of the potential difference between the center of the rod and either of its ends?

A square coil (length of side = 24 cm)of wire consisting of two turns is placed in a uniform magnetic field that makes an angle of 60° with the plane of the coil.If the magnitude of this field increases by 6.0 mT every 10 ms,what is the magnitude of the emf induced in the coil?

An induced emf is produced in

A conducting bar moves as shown near a long wire carrying a constant 50-A current.If a = 4.0 mm,L = 50 cm,and v = 12 m/s,what is the potential difference,V_A − V_B?

Coil 1,connected to a 100 Ω resistor,sits inside coil 2.Coil 1 is connected to a source of 60 cycle per second AC current.Which statement about coil 2 is correct?

The difference between a DC and an AC generator is that

A 500-turn circular loop 15.0 cm in diameter is initially aligned so that its axis is parallel to the Earth's magnetic field.In 2.77 ms the coil is flipped so that its axis is perpendicular to the Earth's field.If a voltage of 0.166 V is induced in the coil,what is the value of the Earth's magnetic field?

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 lowest potential is(are)

A metal blade spins at a constant rate of 5.0 revolutions per second about a pivot through one end of the blade.This rotation occurs in a region where the component of the earth's magnetic field perpendicular to the blade is 30 μT.If the blade is 60 cm in length,what is the magnitude of the potential difference between its ends?

A 50-turn circular coil (radius = 15 cm)with a total resistance of 4.0 Ω is placed in a uniform magnetic field directed perpendicularly to the plane of the coil.The magnitude of this field varies with time according to B = A sin (αt),where A = 80 μT and α = 50π rad/s.What is the magnitude of the current induced in the coil at t = 20 ms?

A planar loop consisting of four turns of wire,each of which encloses 200 cm²,is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 10 mT to 25 mT in a time of 5.0 ms.What is the resulting induced current in the coil if the resistance of the coil is 5.0 Ω?

A small airplane with a wing span of 12 m flies horizontally and due north at a speed of 60 m/s in a region where the magnetic field of the earth is 60 μT directed 60° below the horizontal.What is the magnitude of the induced emf between the ends of the wing?

A metal blade (length = 80 cm)spins at a constant rate of 10 radians/s about a pivot at one end.A uniform magnetic field of 2.0 mT is directed at an angle of 30° with the plane of the rotation.What is the magnitude of the potential difference between the two ends of the blade?

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 (L = 80 cm)moves on two frictionless rails,as shown,in a region where the magnetic field is uniform (B = 0.30 T)and into the paper.If v = 50 cm/s and R = 60 mΩ,what is the magnetic force on the moving bar?