Inducing Currents Lesson 1

Flashcards about inducing currents.

What is electromagnetic induction?

The process of generating current through a wire in a circuit in a changing magnetic field.

What is induced electromotive force?

Potential difference across a wire that results from the production of an electric field.

Who was able to create current from magnetic fields?

Michael Faraday

How did Faraday induce current in a circuit?

By moving a wire through a magnetic field.

What happens when a wire is stationary relative to a magnet?

No current is induced (I = 0).

What relative motion between a wire and a magnet results in maximum induced current?

Perpendicular motion (θ = 90°).

According to the lecture, what must occur to generate an electric current in a wire?

The wire must move through and cut magnetic field lines.

What is the role of a battery in inducing current?

It maintains a potential difference in the circuit.

What is electromotive force (EMF)?

The potential difference given to charges by a battery, measured in Volts (V).

How is current induced when a wire moves perpendicular to a magnetic field?

A force is applied to the charges in the wire, causing positive and negative charges to separate, producing an electric field and a potential difference (induced EMF).

What three factors affect the magnitude of EMF?

1) Strength of the magnetic field (B), 2) length of the wire inside the field (L), 3) the component of the velocity of the length of wire that is perpendicular to the field (v).

According to the lecture, which factor does NOT affect the EMF of a wire moving in a magnetic field?

The diameter of the wire in the field.

What happens to EMF when a wire is moved parallel to a magnetic field?

EMF = 0

What is the formula for calculating current (I) using EMF and resistance (R)?

I = EMF / R

What rule is used to determine the direction of an induced current?

The right-hand rule

How do microphones convert sound to electrical energy?

By electromagnetic induction.

What happens when the diaphragm in a microphone is pushed in?

A current is induced in the coil.

A straight wire is part of a circuit that has a resistance (R) of 0.50 Q. The wire is 0.20 m long and moves at a constant speed of 7.0 m/s perpendicular to a magnetic field of strength 8.0 × 10−2 T. What EMF is induced in the wire?

0.11 V

A straight wire is part of a circuit that has a resistance (R) of 0.50 Q. The wire is 0.20 m long and moves at a constant speed of 7.0 m/s perpendicular to a magnetic field of strength 8.0 × 10−2 T. What is the current through the wire?

0.22 A

A straight wire is part of a circuit that has a resistance (R) of 0.50 Q. The wire is 0.20 m long and moves at a constant speed of 7.0 m/s perpendicular to a magnetic field of strength 8.0 × 10−2 T. If a different metal were used for the wire, increasing the circuit's resistance to 0.78 02, what would the new current be?

0.14 A

You move a straight wire that is 0.5 m long at a speed of 20 m/s vertically through a 0.4-T magnetic field pointed in the horizontal direction. What EMF is induced in the wire?

4V

You move a straight wire that is 0.5 m long at a speed of 20 m/s vertically through a 0.4-T magnetic field pointed in the horizontal direction. The wire is part of a circuit with a total resistance of 6.0 Q. What is the current?

0.67A

A straight wire that is 25 m long is mounted on an airplane flying at 125 m/s. The wire moves in a perpendicular direction through Earth's magnetic field (B = 5.0 × 10-5 T). What EMF is induced in the wire?

0.16V

A straight wire segment in a circuit is 30.0 m long and moves at 2.0 m/s perpendicular to a magnetic field. A 6.0-V EMF is induced. What is the magnetic field?

0.10 T

A straight wire segment in a circuit is 30.0 m long and moves at 2.0 m/s perpendicular to a magnetic field. The total resistance of the circuit is 5.0 Q and A 6.0-V EMF is induced. What is the current?

1.2 A