Chapter 13: Static Electricity

Question 1

Define ‘electric field’

Answer 1

An electric field is a region in which an electric charge experiences an electric force

Question 1

What are the properties of electric charges?

Answer 1

• When two charged particles are brought together, they produce attractive or repulsive forces.
• Like charges repel each other while unlike charges attract each other

Question 2

What is an atom?

Answer 2

An atom consists of electrons orbiting a nucleus made up of neutrons and protons

Question 3

What is the SI unit for electric charge?

Answer 3

Coulomb (C)

Question 4

What is the charge of electrons or protons?

Answer 4

1.6 × 10–19 C.

Question 5

What is it called when at atom loses electrons

Answer 5

• When an atom loses one or more electrons, we call it a positively
  charged particle.

Question 6

What is it called when at atom gains electrons

Answer 6

• When an atom gains one or more electrons, we call it a negatively
  charged particle.

Question 7

What is an electric force?

Answer 7

• An electric charge can exert a force on another nearby charge
  which is known as electric force.
• The electric force can be attractive or repulsive.
• The electric force gets weaker as the nearby charge moves
  further away.

Question 8

How does a gold-leaf electroscope work?

Answer 8

A gold-leaf electroscope allows you to test whether an object is charged.

• An unknown object is brought near the metal plate
• If the leaf deflect, we can conclude that the unknown object has a positive charge.
• If the leaf comes closer to the metal rod, then the charge of the unknown object is negative.

Question 9

What is an electric insulator

Answer 9

An electric insulator is a matewrial which doeks not allow electric charges (electrons) to flow easily. Materials, such as plastic and glass do not conduct electricity because they have no mobile electrons or mobile ions.
When two objects are rubbed together, this results in a transfer of electronsn between the two objects.
The electrostatic series, shown below, will help to determine which material has a higher or lower tendency to become positively chartged when rubbed with another material.

Question 10

What is discharging by heat (ions)?

Answer 10

• Discharging means either neutralising or removing the excess charges on an object

Question 10

Define ‘charging’

Answer 10

Charging by induction is a method used to charge a conductor without the charged object touching the conductor.

Question 11

Define ‘earthing’

Answer 11

Earthing, or grounding, is the discharge of charges by connecting to the ground using a conducting wire.