Exam 23: Faradays Law and Inductance

A 40-turn circular coil (radius = 4.0 cm,total resistance = 0.20 $\Omega$ )is placed in a uniform magnetic field directed perpendicular to the plane of the coil.The magnitude of the magnetic field varies with time as given by B = 50 sin(10 $\pi$ t)mT where t is measured in s.What is the magnitude of the induced current in the coil at 0.10 s?

The magnetic flux through a loop perpendicular to a uniform magnetic field will change

A car with a radio antenna 1.0 m long travels at 80 km/h in a locality where the Earth's magnetic field is 5.0 *10 ^{- 5} T.What is the maximum possible emf induced in the antenna as a result of moving through the Earth's magnetic field?

For the circuit shown,what is the rate of change of the current in the inductor when the current in the battery is 0.50 A?

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

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 m $\Omega$ ,what is the magnetic force on the moving bar?

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?

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 $\overrightarrow { \mathbf { v } }$ 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 coil is wrapped with 300 turns of wire on the perimeter of a square frame (side length = 20 cm).Each turn has the same area as the frame,and the total resistance of the coil is 1.5 $\Omega$ .A uniform magnetic field perpendicular to the plane of the coil changes in magnitude at a constant rate from 0.50 T to 0.90 T in 2.0 s.What is the magnitude of the induced emf in the coil while the field is changing?

A circular loop (area = 0.20 m²)turns in a uniform magnetic field with B = 0.13 T.At an instant when the angle between the magnetic field and the normal to the plane of the loop is ( $\pi$ )rads and is decreasing at the rate of 0.50 rad/s,what is the magnitude of the emf induced in the loop?

Find the magnetic energy stored in the air gap between two very large magnetic pole pieces,one North,one South,each with an area of 100 cm².Assume the 0.05 T magnetic field is uniform within the 2-cm gap.

A long solenoid (radius = 3.0 cm,2 500 turns per meter)carries a current given by I = 0.30 sin(200 $\pi$ t)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?

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 $\vec { B }$ perpendicular to the page so that the graph shown below represents the induced emf.The loop moves at constant velocity $\overrightarrow { \mathbf { v } }$ .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 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 $\omega$ .While it rotates,the point(s)at highest potential is(are)

When a switch is closed,completing an LR series circuit,the time needed for the current to reach one half its maximum value is ____ time constants.

A 400-turn circular coil (radius = 1.0 cm)is oriented with its plane perpendicular to a uniform magnetic field which has a magnitude that varies sinusoidally with a frequency of 90 Hz.If the maximum value of the induced emf in the coil is observed to be 4.2 V,what is the maximum value of the magnitude of the varying magnetic field?

The figure shows an LR circuit with a switch and a 240-volt battery.At the instant the switch is closed the current in the circuit and the potential difference between points a and b,V_ab,are

A loop of wire (resistance = 2.0 m $\Omega$ )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?

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?