Chapter 13 Electricity and Magnetism

What causes static electricity?

• only an object losing electrons
• only an object gaining electrons
• when positive and negative charges balance
• when positive and negative charges no longer balance

A _______ object __________ a positively charged object.

• neutrally charged, repels
• positively charged, repels
• negatively charged, repels
• positively charged, attracts

Which of the following would be a good conductor for a closed circuit?

• wood
• copper
• rubber
• plastic

Where is a magnetic field the strongest?

• at both poles
• in the middle
• at the south-seeking pole
• at the north-seeking pole

A material that conducts electric current poorly is called

• a circuit
• a charge
• a conductor
• an insulator

What would happen to the light bulb in this circuit if one light bulb burns out?

• The other bulbs will remain on
• The other bulbs will be brighter
• The other bulbs will be dimmer
• The other bulbs will go out

How can the strength of an electromagnet be increased?

• by using less current
• by using a smaller magnet
• by using a smaller magnetic core
• by using more turns in the metal coil

Why does a compass needle point in a north-south direction?

• The needle reacts to Earth's magnetic poles.
• The needle forms an electromagnet with Earth's poles.
• The needle is lightweight, so it always spins to the south.
• The needle is pulled in the middle by Earth's equator.

^{In a doorbell, electromagnets help convert _______ to _______ to ____________ energy.}

• magnetic, electric, mechanical
• electric, magnetic, mechanical
• electric, mechanical, magnetic
• mechanical, magnetic, electric

What did Michael Faraday do when he made his dynamo invention?

• He told no one.
• He didn't think he discovered anything.
• He shared his investigation with other scientists.
• He only told Joseph Henry.