Electromagnetism: Faraday and Henry Discovery

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Questions and Answers

What happens to the galvanometer needle when the magnet is moved away from the loop of wire?

The needle shows continuous movement

The needle deflects to the right

The needle deflects to the left (correct)

The needle remains stationary

When there is no change in the magnetic field, the galvanometer measures current.

False

What is the role of the primary coil in Faraday's experiment?

To establish a current and create a magnetic field.

The phenomenon where a current is induced in a coil due to a change in magnetic field is known as __________.

electromagnetic induction Signup and view all the answers

What indicates that a current was established in the secondary coil when the switch is closed?

Galvanometer needle briefly deflects and returns to zero Signup and view all the answers

Moving the loop of wire instead of the magnet produces different results in the experiment.

False Signup and view all the answers

What occurs when the switch in the primary coil circuit is opened?

The magnetic field drops to zero, causing the galvanometer to deflect in the opposite direction. Signup and view all the answers

Match the terms with their corresponding descriptions:

Primary Coil = Creates a magnetic field when current flows Galvanometer = Measures the induced current Iron Ring = Enhances the magnetic field Secondary Coil = Induces current based on changes in the magnetic field Signup and view all the answers

Who simultaneously discovered that a magnetic field can produce an electric current?

Joseph Henry and Michael Faraday Signup and view all the answers

A static magnetic field can induce an electric current in a stationary conducting wire.

False Signup and view all the answers

What is the device used to detect the presence of electric current called?

galvanometer Signup and view all the answers

The current induced by changing magnetic fields is referred to as __________ current.

induced Signup and view all the answers

What happens when a magnet is moved towards a loop of wire?

An induced current is detected Signup and view all the answers

Match the following scientists with their contributions related to electromagnetic induction:

Joseph Henry = Co-discovered electromagnetic induction Michael Faraday = Co-discovered electromagnetic induction James Clerk Maxwell = Formulated the theory of electromagnetism Nikola Tesla = Contributed to the development of AC current Signup and view all the answers

What occurs when the magnet is moved away from the loop of wire?

A current is detected in the opposite direction. Signup and view all the answers

The change in the number of magnetic field lines passing through the loop causes the __________ of current.

induction Signup and view all the answers

Study Notes

Magnetic Fields and Electric Currents

Current-carrying wires generate magnetic fields while magnetic fields influence current-carrying wires.
Joseph Henry and Michael Faraday independently discovered that changing magnetic fields can induce electric currents.

Electromagnetic Induction

Static magnetic fields do not induce electric currents in stationary conducting wires.
Changing magnetic fields can generate currents, demonstrated through experiments with moving magnets and loops of wire.
Using a galvanometer (a sensitive ammeter), the presence of electric currents is detected during motion.
Movement of a bar magnet towards a wire loop creates an induced current detectable by the galvanometer, indicating a change in magnetic field lines.
The direction of the induced current is determined by the direction of the magnet's movement.
When the magnet is moved away from the wire loop, the induced current reverses direction.
If there is no relative motion between the magnet and the wire, no current is induced.

Faraday’s Experiment

Faraday’s experiment involved a primary coil wrapped around an iron ring, with a secondary coil also on the ring.
The primary coil is connected to a battery, enabling a magnetic field when current flows.
When the switch is closed, current flows in the primary coil, temporarily inducing a current in the secondary coil, as signified by the galvanometer.
Opening the switch cuts off current, collapses the magnetic field, and again induces a brief current, but with reversed direction.
This experiment parallels earlier experiments with magnets, highlighting that the source of the magnetic field can vary (current vs. magnet).

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Description

This quiz explores the foundational discoveries of electromagnetic induction by Joseph Henry and Michael Faraday in the 19th century. Learn about how a magnetic field can generate an electric current and the significance of their work in the field of physics and engineering. Test your knowledge on the principles of electromagnetism and its historical context.