PHY_10_59_V2_P_Artificial magnets. Solenoid
Оценка 4.9

PHY_10_59_V2_P_Artificial magnets. Solenoid

Оценка 4.9
ppt
08.05.2020
PHY_10_59_V2_P_Artificial magnets. Solenoid
PHY_10_59_V2_P_Artificial magnets. Solenoid.ppt

Lesson Objectives By the end of the lesson learners will be able: 10

Lesson Objectives By the end of the lesson learners will be able: 10

Lesson Objectives

By the end of the lesson learners will be able:

10.4.1.4 – to make an artificial magnet empirically and explain the scopes of its application;
10.4.1.5 – to explain the factors having an effect on a magnetic field of a solenoid;

Keywords English Russian Kazakh

Keywords English Russian Kazakh

Keywords

English

Russian

Kazakh

Direct current

Alternating current

Magnetization

Demagnetization

solenoid

Electromagnet

Magnetic field

polarity

Hard and Soft Magnetic Materials

Hard and Soft Magnetic Materials

Hard and Soft Magnetic Materials

Permanent magnets are made of magnetically HARD materials such as steel, alcomax, magnadur. These materials retain their magnetisation once magnetised. Hard to magnetise.

Magnetically SOFT materials, such as iron, mumetal lose their magnetisation easily. They suitable for temporary magnets such as electromagnets. Easy to magnetise.

Making and Destroying Magnets Magnetization stroke, coil and solenoid methods

Making and Destroying Magnets Magnetization stroke, coil and solenoid methods

Making and Destroying Magnets

Magnetization

stroke, coil and solenoid methods
Use direct current.

Demagnetization

Heating
Drop it down several times
Use alternating current

Stroke Methods

Polarity of Magnetized Materials

Direct Current Magnetization Coil and

Direct Current Magnetization Coil and

Direct Current Magnetization

Coil and Solenoid Magnetization

Magnetic Keepers

AC Demagnetization

Induced Magnetism Magnetism can be induced in a magnetic material if it is placed within a magnetic field

Induced Magnetism Magnetism can be induced in a magnetic material if it is placed within a magnetic field

Induced Magnetism

Magnetism can be induced in a magnetic material if it is placed within a magnetic field.

If the material is magnetically hard it will retain its magnetism once removed from the field.

Certain rocks in the Earth’s crust such as lodestone have been magnetised in this way by the Earth’s magnetic field.

iron bar

Induced Magnetism 9-May-20 7

Induced Magnetism 9-May-20 7

Induced Magnetism

9-May-20

7

Solenoid A solenoid is a coil of wire carrying an electric current

Solenoid A solenoid is a coil of wire carrying an electric current

Solenoid

A solenoid is a coil of wire carrying an electric current.

The magnetic field is similar in shape to that around a bar magnet.

The strength of the field increases with:
the electric current
the number of turns in the coil

The Right-Hand Grip Rule (for Poles)

The Right-Hand Grip Rule (for Poles)

The Right-Hand Grip Rule (for Poles)

Grip the coil with the RIGHT hand.
The fingers are placed in the direction that the eclectic current flows around the coil.
The thumb points towards the north pole end of the coil.

N

S

Solenoid Polarity from Side view

Solenoid Polarity from Side view

Solenoid Polarity from Side view

Complete the diagrams below:

1. Locate north

3. Add current direction

2. Locate south

N

S

4. Add coils

N

Electromagnets An electromagnet consists of a current carrying coil wrapped around an iron core

Electromagnets An electromagnet consists of a current carrying coil wrapped around an iron core

Electromagnets

An electromagnet consists of a current carrying coil wrapped around an iron core.

Build your electromagnets

You need the following materials:
Large iron nail (approximately 3 inches in length)
Thin coated copper wire.
Dry cell batteries.
Electric tape.
Iron fillings, paper clips and other magnetic items

Activity

Activity

Activity

Activity

Activity

Activity

True or False?

True or False?

True or False?

AfL 1. The magnetic field surrounding a wire is strongest:

AfL 1. The magnetic field surrounding a wire is strongest:

AfL

1. The magnetic field surrounding a wire is strongest:
A. close to the wire
B. far from the wire
C. the field does not vary with distance

2. Electromagnet polarity can be reversed by:
A. increasing current
B. decreasing current
C. reversing current direction

3. An electromagnet’s strength can be adjusted by:
A. adjusting the number of coils
B. adjusting the amount of current
C. both A and B
D. neither A nor B


KEY 1. A 2. C 3. B

KEY 1. A 2. C 3. B

KEY

1. A
2. C
3. B

Activity Explain the applications of electromagnets in

Activity Explain the applications of electromagnets in

Activity

Explain the applications of electromagnets in
Scrap yard crane
The electric door bell
The relay switch
Car ignition key

Uses of Electromagnets 1. Scrap yard

Uses of Electromagnets 1. Scrap yard

Uses of Electromagnets

1. Scrap yard Crane

The iron core of the electromagnet is a SOFT magnetic material.

When current flows the iron becomes strongly magnetised and so picks up the scrap iron and steel.

When the current is turned off the iron loses its magnetisation and so releases the scrap.

The Electric Bell When the push switch is closed current flows around the circuit turning on the electromagnet

The Electric Bell When the push switch is closed current flows around the circuit turning on the electromagnet

2. The Electric Bell

When the push switch is closed current flows around the circuit turning on the electromagnet.

The soft iron armature is pulled towards the electromagnet and the hammer hits the gong.

This causes the contact switch to open cutting off the electric current.

The spring now pulls the armature back again closing the contact switch.

Current now flows again and the hammer hits the gong again.

gong

hammer

electromagnet

push switch

spring

contact switch

soft iron armature

Label the diagram of the electric bell be :

Label the diagram of the electric bell be :

Label the diagram of the electric bell be:

Contact switch

The Relay Switch A relay switch is a way of using a low voltage circuit to switch remotely a high voltage (and possibly dangerous) circuit

The Relay Switch A relay switch is a way of using a low voltage circuit to switch remotely a high voltage (and possibly dangerous) circuit

3. The Relay Switch

A relay switch is a way of using a low voltage circuit to switch remotely a high voltage (and possibly dangerous) circuit.

When switch A is closed, the small current provided by the cell causes the electromagnet to become magnetised..

The iron armature is then attracted to the electromagnet causing the springy contact switch B to close in the high voltage circuit.

switch A

springy contact switch B

iron armature

hinge

electromagnet

to high voltage circuit

Circuit Breaker Current normally flows between terminals

Circuit Breaker Current normally flows between terminals

4. Circuit Breaker

Current normally flows between terminals A and B through the contact and the electromagnet.

When the current in a circuit increases, the strength of the electromagnet will also increase. This will pull the soft iron armature towards the electromagnet.

As a result, spring 1 pulls apart the contact and disconnecting the circuit immediately, and stopping current flow.

The reset button can be pushed to bring the contact back to its original position to reconnect the circuit

1

2

5. Car Ignition/Spark Plug

5. Car Ignition/Spark Plug

5. Car Ignition/Spark Plug

Fill in the gaps below: A wire carrying an electric ______ produces a magnetic field

Fill in the gaps below: A wire carrying an electric ______ produces a magnetic field

Fill in the gaps below:
A wire carrying an electric ______ produces a magnetic field. This field increases in ________ if the current is increased.
A ________ is a coil of wire carrying an electric current. The field produced increases in strength if the number of _____ in the coil is increased or if _____ is placed inside the coil.
An ____________ consists of a coil of a solenoid wrapped around an iron core. Iron is a ______ magnetic material that loses its magnetisation once the current in the coil is switched off.

solenoid

strength

iron

soft

turns

current

electromagnet

WORD SELECTION:

solenoid

strength

iron

soft

turns

current

electromagnet

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