Question

Objective: In this lab you will investigate magnets, electromagnets, electric motors, generators, and magnetic inductance and discuss their applications.  

Part 1: Magnetic Fields

1. How do the lodestone and round magnet affect the compass needle?

2. How can you tell which side is North and South?

3. How is an electromagnet similar to a permanent magnet? How is it different?

Part 2: Electric Motors

1. Describe how a DC electric motor works.

Part 3: Magnetic Induction

1. In the setup with a gilley coil connected to a galvanometer, how is a current produced in the wire?

2. What happens to the direction of the current if you flip the magnet around?

3. Watch Demo 1.
   1. Explain how the oscilloscope can display the signal from the function generator even though they are not connected.

2. As the gilley coils move farther apart, what happens to the signal?

4. Watch Demo 2.
   1. What causes the LED to turn on?

2. What are some practical applications of this concept?

5. Watch Demo 3.

Explain how magnetic induction is involved in producing the sound.

Answer 1

Sol Load Stone has magnetic property Compass needle By deflect which it Can affect the the Compass needle . The side which attracts is South of the Load stone north of the Compass needle and vice -versa. is off when Current passes through the electromagnetic , then its attains the magnetic property and behaves likes a Permanent magnet, But when Current then it loose its magnetic property whereas permanent magnet always have magnetic property it Gooses. 2. Working of Electric motor will never Dc Dc motor is Device which a Armature Coil Converts the direct current into work It on the HC principle of Lorentz law 2 mechanical works the Current carrying Conductor placed in a magnetic field experience a force and flemming's left hand-rule gives the direction of the force." Adjacent figure shows the schematic diagram of permanent Electric motor. imagnet Brushes DC In Dc motor Armature Coil TE Battery and stater Are two the rotating part armature Coil main motor. Armature and parts of De stater is their connected to Stationary part. The power supply, is

of the The armature Coil Consists of the Comma forter Switch brushes. The Commutator rectifier and AC Converts the into DC armature and brushes induced transfer in the Current the from rotating part motor to the stationary enternal load . The armature is placed between the north South poles of permanent Electromagnet when the Dc Supply is given to the annature Coil the current Starts flowing through it. This current develops its own field around interaction of the feeds the resultant the Coil. by the field develops acrose the Conductor . This tries to rotate the Conductor restore the Conductor to its original position. This generates torque the Coil which proportional to the number of turns. This induced torque Causes Contineously Now the rotor to move 3 we have from Faraday's laws of Electromgenetic induction E- is near enf develops also revelse we induction of Induced enf N doo dt when magnet, moved the gilley Coil then induced in the Coil it makes the deflection in the Galvanometer. Direction of Current when flip the directson of a magnet. Due to from function generentor to oscilloscope signal Can be displayed eventhough they not connected gilley Coil farther As apart the strength movy induced Current decreases. of induced signal or LED indured turn due to voltage induced current. 4. such as Transformers motors measuring devices works on the principle of Electromgenetic induction. are 2 3. will ar many devices