P4 - Static Electricity

Question 1

What charge do Electrons have?

Answer 1

Electrons have a negative charge.

Question 2

What happens when two insulating materials are rubbed together?

Answer 2

When two insulating materials are rubbed together, electrons will be scraped off one and dumped on the other.

• This leaves a positive charge on one due to a lack of electrons, this is because it has lost electrons ( - ), so it leaves it positively charged
• It leaves a positive static charge on the other due an excess of electrons - it has gained electrons.

Question 3

What does the direction of electrons transferred depend on?

Answer 3

Which way the electrons are transferred depends on the two materials involved, e.g.

• With a polythene rod, electrons move from the duster to the rod
• With an acetate rod, electrons move from the rod to the duster.

Question 4

What happens to the electrons on a polythene rod?

Answer 4

The electrons will move from the duster to the rod.

Question 5

What happens to the electrons on an acetate rod?

Answer 5

The electrons move from the rod to the duster.

Question 6

What do all Electrically charged objects do?

Answer 6

Electrically charged objects attract small neutral objects placed near them.
- An example is the polythene and acetate rods being rubbed on a duster.

Question 7

What is a positive static charged caused by?

Answer 7

A positive static charge is caused by electrons moving away elsewhere, the charge itself never moves.

Question 8

How are sparks and shocks caused?

Answer 8

• if enough static charge builds up, it can suddenly move which can cause sparks or shocks that can be dangerous.

Question 9

How can a charged conductor be discharged safely?

Answer 9

• A charged conductor can be discharged safely by connecting it to earth with a metal strap, this is called earthing.
• the electrons flow down the strap to the ground if the charge is negative.
• the electrons will flow up the strap from the ground if the charge is positive.

Question 10

What happens to opposite charges?

Answer 10

Opposite electric charges are attracted to each other.

Question 11

What happens to like charges?

Answer 11

Like charges will repel each other.

Question 12

What is the correlation between forces and distance?

Answer 12

Forces get weaker as the distance increases.

Question 13

What are ions?

Answer 13

Ions are atoms or molecules that become charged.