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Answers to Readers' Questions on Physical Science:

Electricity Basics

The following 4 comments and questions have been sent in. They are listed according to date.

List of first 10 items

• Difference between dc and ac?
• Which type of electric current is more dnagerous?
• Why can't static charges be on a copper rod?
• Where is the magnetism strongest?

Next 10

Difference between dc and ac?

Question

June 19, 2009

hey there can u please help me to find the difference between dc and ac and the explanation of both REPLY PLEASE SIR..

chokwe - South Africa

17925

Answer

Direct current electricity (DC) usually comes from batteries and flows in one direction in a wire. Alternating current electricity (AC) moves back and forth in a wire. Both will light a light bulb, but AC is required for many electronic devices.

See our lessons at:
http://www.school-for-champions.com/science/dc.htm
http://www.school-for-champions.com/science/ac.htm

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Which type of electric current is more dnagerous?

Question

April 18, 2009

which of the two currents AC or DC is more dangerous and why?

Neelam - India

17629

Answer

If a person would touch a high voltage AC wire, he might quickly drop it after getting a shock. But if it was a high voltage DC wire, his muscles would tense and he could not drop the wire. Thus DC is more dangerous.

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Why can't static charges be on a copper rod?

Question

July 8, 2008

Why charge (static charge) can not be developed on copper rod ?

subash - India

16191

Answer

Copper can collect negative electrical charges. See:
http://www.school-for-champions.com/science/static_materials.htm

But since copper is a conductor of electricity, the charges are quickly dissipated. A non-conductor of electricity will keep static charges on its surface.

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Where is the magnetism strongest?

Question

May 31, 2008

1) I just wanted to know that where is the magnetic strongest effect of a magnet strongest?
2)how is magnetic poles labeled?
3)what are the properties that magnet have?
4)and how is Earth like a bar magnet?

Irene - USA

16017

Answer

The magnetic effect is the strongest right at the end or pole of the magnet.

Read out lessons on magnets for more information: http://www.school-for-champions.com/science/magnetism.htm

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