Topic 11 👱‍♀️⚡️

Question 1

What can happen when insulating materials are rubbed together?

Answer 1

They can become (statically) electrically charged.

Question 2

Why can insulators become electrically charged when rubbed together?

Answer 2

• Electrons transfer from one material onto the other.
• The material gaining electrons becomes negatively charged.
• The material losing electrons becomes equally positively charged.

Question 3

What would happen when two electrically charged objects are brought close together?

Answer 3

They exert a force on eachother

Question 4

What happens when two identically charged objects are brought close together?

Answer 4

They exert a repulsive force on eachother and repel.

Question 5

What happens when two oppositely charged objects are brought close together?

Answer 5

They exert an attractive force on each other and attract

Question 6

Give an example of a non-contact force.

Answer 6

The repulsive or attractive force acting between two electrically charged objects.

Question 7

Why do we feel an electric shock?

Answer 7

• When an object builds up an electrostatic charge, it needs to be ‘earthed’ via a conductor.
• electrons flow to/from the earth to balance the charge.
• this canalso occur if you touch a charged object whilst you are earthed.
• If earthed occurs through a person/animal, it causes an electric shock.

Question 8

Why does lightning occur?

Answer 8

• Clouds can build up an electrostatic charge.
• When this charge becomes large enough, the clouds discharge via the air to the earth.
• This is known as lightning.

Question 9

Why does a charged balloon stick to a wall?

Answer 9

When a positively charged ballon is placed next to a wall the positive charges near the balloon get repelled to other parts of the wall.
This leaves an area of the wall with a negative charge, which attracts the positively charged ballon towards the wall, making the balloon stick.

Question 10

How does earthing remove excess charge?

Answer 10

It provides a path with a low resistance for the electrons to flow either from the device or towards the device to reduce the charge build up.

Question 11

How does static electricity cause danger when fuelling cars?

Answer 11

• Static charge can build up due to the friction between the pipes and the fuel,
• When the charge builds up, a spark may be discharged.
• The spark could start a fire if it reacts with the flammable fuel.
• This is resolved by earthing the vehicle and pump.

Question 12

What is an electric field?

Answer 12

A region where an electric charge will experiment a non-contact force.

Question 13

What direction do the field lines in an electric field point?

Answer 13

In the direction that a positive charge would move (experience a force).

Question 14

Describe the appearance of electric field lines in a parallel field.

Answer 14

Straight lines, which are parallel to eachother and point from the positive plate to the negative plate. At the edges, the lines are partially curved.

Question 15

How can you tell whether a field is stronger through diagrams?

Answer 15

The field lines being closer together shows a stronger field.

Question 16

How can you use electric fields to explain static electricity?

Answer 16

• The object that is statically charged will generate an electric field.
• This field attracts the electrons on other objects causing a flow of charge resulting in sparks.