8th Grade - Science Fall Final

Which of the two below result in an attractive force

• a positive charge and a negative charge

• two south poles

• two negative charges

• a north pole and a south pole

Static electricity is the buildup of charges between two objects. What best explains why a balloon is attracted to hair when the two have been rubbed together?

• They both have positive charges

• They both have positive charges

• They both have neutral charges

• They both have opposite charges

Static electricity is the buildup of charges between two objects. What best explains why a balloon is attracted to hair when the two have been rubbed together?

• They both have positive charges

• They both have positive charges

• They both have neutral charges

• They both have opposite charges

Two bar magnets are held close together. They are released and allowed to move freely. The bar magnets quickly come together. Which explains best why this happen?

• the poles facing one another are both south poles

• the poles facing one another are opposite poles

• the poles facing one another are both north poles

• one magnet was bigger than the other

Fredrick sets paper clips out on a table. He then takes a magnet, places it directly beneath the paper clips under the table, and moves the magnet. He finds that the paper clips move with the magnet. Why does this happen?

• magnetic force is a repellent

• magnetic forces act on wood, like in the table

• the paper clips are feeling the gravitational force of the magnet

• magnetic forces act at a distance, even between objects

In an electromagnet, coils of wire are wrapped around a magnetic object to generate a magnetic field. What is the relationship between the number of coils and the strength of the magnetic field?

• the more coils an electromagnetic has, the stronger the magnetic field

• the more coils an electromagnetic has, the weaker the magnetic field

• the larger the metal object, the stronger the magnetic fiel is

• there is no relationship between the number of coils and the strength of a magnetic field

What is the cause of electricity

• magnetism

• gravity

• moving electrons

• lightning

Atoms that have a positive charge will be attracted to atoms with a ________charge

• positive

• negative

• no charge

This force occurs when there is an attractive and repulsive force between two poles

• electric

• electromagnetism

• magnetism

• static electricity

In a magnet the opposite poles will

• attract

• repel

• neither