# Feedback Comments on Magnetism

by Ron Kurtus

A total of 677 comments and questions have been sent in. They are listed according to date.

You can read them to further your understanding of the subject.

## List of most recent 10 letters

### Country

Electromagnetism Relationship between magnetic force and electricity Nigeria

Magnetism Magnetic alignment Ghana

Basics of Magnetism Reducing permanent magnetism New Zealand

Magnetic Materials Wands free books on EMF Ethiopia

Moving Charges Create Magnetic Field How is magnetic field created? India

General Device using small disc magnet Canada

Solenoids Solenoid and electromagnet India

Basics of Magnetism Questions on electromagetism India

Electromagnetic Devices How do electromagnets work in railway signals? India

Electromagnets Placing electromagnet inside another electromagnet USA

Next 10

## Relationship between magnetic force and electricity

Topic: Electromagnetism

### Question

October 23, 2018

my question is, what is the relationship between magnetic force and electricity?

Abdulrahman - Nigeria

28756

### Answer

See Moving Electrical Charges Create Magnetic Field. It shows that when electrical charges move, they create a magnetic force field. Likewise, a magnetic force can create electricity. See Basics of Electromagnetism.

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## Magnetic alignment

Topic: Magnetism

### Question

October 8, 2018

what is in the iron that makes magnetic substance attracted by it

obed - Ghana

28741

### Answer

It is the alignment of the electrons. See: Factors Determining Magnetic Properties.

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## Reducing permanent magnetism

Topic: Basics of Magnetism

### Question

October 6, 2018

If you have a weak permanent magnet and wind a multi turn coil around it and then pass an electrical current through the coil, can you negate the magnet strength of the magnet?
Will a specific current be required to reduce the magnet strength to exactly zero?

Charlie - New Zealand

28738

### Answer

You can demagnetize a permanent magnet by hitting it with a hammer or heating it to a sufficient temperature. Both cases disrupt the alignment of the atoms.

The problem with using a coil is that the atoms can be realigned into a different direction, thus still maintaining the magnetism. The only way to reduce the strength of the magnet is to get some or all of the atoms in random orientation.

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## Wands free books on EMF

Topic: Magnetic Materials

### Question

May 30, 2018

Hello I am bereket, age 20 and I'm from Ethiopia. I want to ask you how I can get free online books on EMF.

Bereket - Ethiopia

28571

### Answer

There are some free downloads on EMF from Free Books - EMF.

I'm not sure how extensive they are, but they might give you what you want.

Best wishes for success in your studies.

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## How is magnetic field created?

Topic: Moving Charges Create Magnetic Field

### Question

November 7, 2017

how megnetic field created around electric current

ravi - India

28312

### Answer

Electrical charges have an electric field around them. When the charges move a magnetic field is created perpendicular to that movement. An electric current consists of moving electrical charges.

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## Device using small disc magnet

Topic: General

### Question

September 6, 2017

Good morning Ron. My son and I are developing a low tech medical device that relies on the attraction between a small disc magnet 20 mm x 2 mm and a similarly sized flat washer. We're having a problem with the amount of attraction between the two and need to increase it and are thinking about increasing the size of the magnet or the washer but are constrained in doing this due to physical dimensions. Is there anything readily available such as a flat washer or disc with a higher than normal iron content that would cause the magnet to be more strongly attracted to it? Many thanks!

Niall - Canada

28214

### Answer

You might try a Neodymium disc magnet. They are small, strong and inexpensive and can be bouht through Amazon.com or other outlets.

I hope that helps. Best wishes for success with your device.

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## Solenoid and electromagnet

Topic: Solenoids

### Question

June 13, 2017

Why solenoid is used for making electromagnet

Nishant - India

28091

### Answer

A solenoid is an electromagnet without the iron core in it. The solenoid can be used to pull a core inside it.

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## Questions on electromagetism

Topic: Basics of Magnetism

### Question

February 17, 2017

DC Electromagnet.
1. Ratio of Core area & Poles face area.
2. What is ATTRACTION POWER?
3. If three sides of magnet is covered with non magnetic material will there be more force on pole faces.
4. Construction & operation details of
ELECTRO-PERMENANT MAGNETS

tks. rgds, Vish

Viswanatan - India

27886

### Answer

See our lessons on Electromagnetism. They should help answer some of your questions.

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## How do electromagnets work in railway signals?

Topic: Electromagnetic Devices

### Question

February 14, 2017

How electromagnet works in railway signals?

Harsh - India

27879

### Answer

Railway signals can be flashing lights or a moving barrier.

An electromagnet could be used as a solenoid to turn on or turn off the railway signals.

The barrier is usually moved by an electric motor.

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## Placing electromagnet inside another electromagnet

Topic: Electromagnets

### Question

February 5, 2017

I have a new found curiosity for electromagnets. I'm not a scientist or even a student... just curious. What would happen if your electromagnet core contained another electromagnet?

Ron - USA

27857

### Answer

If the core is movable, you would have a solenoid of sorts. (See Solenoids are Electromagnetic Devices).

Instead of having a movable iron core or magnet core, you would place an electromagnet there. This would allow movement of the core to be finely tuned. However, I don't think I've even seen such a configuration.

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Next 10

## Summary

Hopefully, this reader feedback has helped provide information about Magnetism issues.

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