Electricity

In a neutral atom, the number of electrons is equal to the number of _______.

• Neutrons
• Orbits
• Protons
• subatomic particles

If two charges repel each other, the two charges must be

• Positive and neutra
• Positive and negative
• positive and neutral
• negative and negative

An object becomes charged when the atoms in the object gain or lose

• electrons
• protons
• neutrons
• all of the above

If you rub a glass rod with a piece of silk, the rod becomes positively charged. This means that

• friction destroyed electrons in the rod.
• the silk has become negatively charged.
• protons have moved to the rod.
• glass attracts more protons.

Objects that have opposite charges

• are attracted to each other, and the force between the objects pulls them together.
• are attracted to each other, and the force between the objects pushes them apart.
• are repelled by each other, and the force between the objects pulls them together.
• are repelled by each other, and the force between the objects pushes them apart.  

A region around a charged particle that can exert a force on another charged particle is called an

• electric pulse.
• electric charge.
• electric force.
• electric field.

Two balloons are hanging from a stick.

Both balloons have a positive charge.

How would you expect the balloons to move?

• there would be no movement

• towards each other

• away from each other

Two balloons are hanging from a stick.

One balloon has a positive charge and the other has a negative charge.

How would you expect the balloons to move?

• there would be no movement

• towards each other

• away from each other

The ball on the string is being repelled (pushed away) by the metal bar.

What must be the charge on the ball?

• postivie

• neutral

• negative

Read the following statements about electric force. Which statement is NOT CORRECT?

• The smaller the distance between 2 charged particles, the stronger the electric force.

• The higher the charges involved, the stronger the electric force.

• The greater the distance between 2 charged particles, the weaker the electric force.

• The smaller the distance between 2 charged particles, the weaker the electric force.