"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 4

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"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 4

New knowledge exploration

1. Electromagnet

Definition: An energized solenoid inserted into an iron core is called an electromagnet.

Working principle: Use the magnetic effect of electric current to work.

So what factors are related to the magnetic size of electromagnets? Let’s explore it together.

2. How to make the electromagnet stronger

(1) Conjecture: The strength of the magnet may be related to the size of the current, the number of turns of the coil and the presence or absence of an iron core.

(2) Experimental equipment: power supply, switch, rheostat, wire, ammeter, pin, electromagnet

(3) Design circuit diagram:

(4) Experimental method: Control variable method

Production: Use an insulated conductor to wind 50 turns on one iron nail, and wind 100 turns on the other iron nail to become two electromagnets with different numbers of turns. Try turning on the power and see if it can suck the nails?

Experimental steps:

1. Move the slide of the sliding rheostat and change the current. Observe, how many small nails are attracted by the magnet? Is the magnet strong or weak?

Conclusion: The greater the current, the stronger the magnetism.

2. Use a coil with a different number of turns and observe how many small nails the magnet attracts? Is the magnet strong or weak?

Conclusion: The more turns, the stronger the magnetism.

3. Remove the iron core and observe, how many small nails are attracted by the magnet? Is the magnet strong or weak?

Conclusion: Without an iron core, the magnetic field will be weaker.

3. Advantages of electromagnets

(1) The magnetism of the electromagnet can be controlled: it is magnetic when the power is on, and non-magnetic when the power is off.

(2) The magnetic strength of the electromagnet can be controlled: the magnetic strength of the electromagnet can be changed by changing the size of the current.

(3) The direction of the magnetic pole of the electromagnet can be controlled: the magnetic pole of the electromagnet can be changed by changing the direction of the current.

4. Application of electromagnets

Maglev trains, cranes, telegraph machines, generators, electric motors.

5. Electromagnetic relay

1.What is an electromagnetic relay?

It is a device that uses the switching of low voltage and weak current circuits to indirectly control high voltage and high current circuits.

2. What is the essence of electromagnetic relay?

It is a switch that uses electromagnets to control a working circuit.

3. Structure and working principle of electromagnetic relay

It consists of low-voltage control circuit and high-voltage working circuit.

Control circuit: low voltage power supply, switch, electromagnet

Working circuit: high voltage power supply, contacts, electrical appliances

Practice in class

1. The magnetic strength of the energized solenoid is related to ___________, ___________ and ___________.

2. As shown in the figure, when the slider of the sliding rheostat moves to the right, the current in the circuit will _______ and the magnetism in the electromagnet will _______.

3. As shown in the picture, to make the electromagnet have the strongest magnetism, the correct connection method is ( )

A. S1 is connected to 1, S2 is connected to 3

B. S1 is connected to 1, S2 is connected to 4

C. S1 is connected to 2, S2 is connected to 4

D. S1 is connected to 2, S2 is connected to 3

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For more information about the PPT courseware "From Compass to Maglev Train Current's Magnetic Field", please click the From Compass to Maglev Train's ppt Current's Magnetic Field ppt tag.

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 3:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 3

Situation introduction

Are magnetism and electricity related?

magnet charged body

Can attract magnetic substances and attract light and small objects

There are North and South poles..

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 2:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 2

Review: What is observed when a small magnetic needle is placed around a bar magnet? What is the reason?

The small magnetic needle is observed to deflect.

Reason: Because there are magnetic fields around the magnet...

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware

1. Oersted’s experiment

1. Place a wire parallel to the small magnetic needle. When the circuit wire is connected, the current passes through the small magnetic needle. When the circuit wire is disconnected, the current passes through the small magnetic needle.

File Info

Update Time: 2024-11-13

This template belongs to Physics courseware Shanghai Science Edition Ninth Grade Physics industry PPT template

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