Static electricity

Question 1

What is formed when electrons are added or removed from an atom?

Answer 1

An ion

Question 2

Why cannot protons be removed?

Answer 2

As they are bound in the nucleus

Question 3

What happens when two different insulators are rubbed together?

Answer 3

If two different insulators are rubbed together, friction can cause electrons to transfer between them

Question 4

What happens if there are more protons than electrons?

Answer 4

The object will be positively charged

Question 5

What happens if there are more electrons than protons?

Answer 5

The object will be negatively charged

Question 6

What is the unit for charge?

Answer 6

The coulomb (C)

Question 7

If an insulator is rubbed with a cloth, how can it become charged?

Answer 7

• Electrons move from the cloth to the insulator + the insulator ends up with an overall negative charge
  OR
• Electrons move from the insulator to the cloth + the insulator ends up with an overall positive charge

Question 8

What is an electric field?

Answer 8

A region where an object with charge experiences a force

Question 9

What are the main points to remember when drawing electric field lines?

Answer 9

• lines with arrows
• direction of arrow is the direction of the force on a positive charge at that point
• the closer together the lines the stronger the field
• field lines must never overlap/cross

Question 10

Where is the electric field strongest?

Answer 10

At the surface

Question 11

Why do sparks occur?

Answer 11

A very strong electric field can ionise air (remove electrons)
Ions can conduct electricity- this is the spark

Question 12

What happens when two positively charged objects are brought near each other?

Answer 12

They repel

Question 13

How can two insulating materials become electrically charged?

Answer 13

When they rub against each other, friction causes the transfer of negatively charged electrons from one material to the other

Question 14

If you become electrically charged, how do you get a shock if you touch a metal object?

Answer 14

There is a potential difference between you and the Earth. When you touch the metal object, electrons either move from your body to the metal, or from the metal to your body

Question 15

What happens when a positively charged object is brought near a negatively charged object?

Answer 15

They attract

Question 16

How can static electricity cause sparks?

Answer 16

If the electric field is strong enough, the air can become ionised and become an electrical conductor, allowing charge to flow

Question 17

What does it mean if an object is negatively charged?

Answer 17

That it has gained negatively charged electrons

Question 18

What is an electric field?

Answer 18

A region where a charged object experiences an electrical force

Question 19

What does it mean if an object is positively charged?

Answer 19

That it has lost negatively charged electrons

Question 20

What happens to the strength of an electric field as you move further away from a charged object?

Answer 20

The field becomes weaker

Question 21

What happens when two negatively charged objects are brought near each other?

Answer 21

They repel

Question 22

When two insulating materials are rubbed together, how do their charges compare?

Answer 22

The positive charge is equal in size to the negative charge

Question 23

Where is the electric field surrounding a charged object the strongest?

Answer 23

Close to the object