Electricity

Question 1

What is static electricity

Answer 1

Static electricity is the build up of charge caused by an imbalance of electrons on the surface of a material

Question 2

Why does static electricity occur best at insulators

Answer 2

Electrons in insulators cannot move and thus cannot escape the the object, allowing for the build up of static electricity

Question 3

What are conductors

Answer 3

Conductors are materials that allow electricity to flow through them. They have free moving, delocalized electrons that can move freely between them

Question 4

What are insulators

Answer 4

Insulator’s are materials that cannot conduct electricity

Question 5

List some examples of conductors

Answer 5

Metals
Graphite
Water
People

Question 6

List some examples of insulators

Answer 6

Plastic
Glass
Rubber
Porcelain

Question 7

What are some everyday examples of static electricity

Answer 7

Lightning
Rubbing a balloon on your hair causes it to stick onto them

Question 8

What are two ways to create static electricity

Answer 8

Friction
Induction

Question 9

How is static electricity created by friction

Answer 9

When a cloth is rubbed against an object, some electrons are rubbed off onto the object because of friction. This increase in electrons leads to the object acquiring a negative charge as it has more electrons than protons

Question 10

Similar charges….

Answer 10

repel

Question 11

Opposite charges…..

Answer 11

attract

Question 12

Why is charge not built up when you are holding a conductor

Answer 12

Conductors are materials that allow electricity to flow through them. Therefore, when rubbing a conductor, the extra electrons can just escape from the object to your hands and then to the ground because of the presence of a conducting path

Question 13

How does an electroscope become charged by induction

Answer 13

When a negatively charged object is brought close to the electroscope, the electrons in the electroscope are repelled by those of the object, causing them to move to the bottom. This results in both the metal rod and the leaf acquiring a negative charge. Since they both have the same charge, the leaf will be repelled by the rod causing it to rise

Question 14

How does an earthed electroscope become charged by induction

Answer 14

When a negatively charged object is brought close to an earthed electroscope, the electrons in the electroscope are repelled by those in the object. Because of the existence of a conducting path, these electrons can escape to the ground, resulting in the electroscope acquiring a positive charge. Since both the rod and the leaf have the same positive charge, they repel causing the leaf to rise

Question 15

How does a photocopier work

Answer 15

The copying plate is positively charged and an image of the page you want to copy is projected on the plate. The surface then is covered with negatively charged black power, which is attracted to the positively charged image area. Lastly, the powder is the fused to the paper by heat

Question 16

How do inkjet printers work

Answer 16

Firstly, charged droplets of ink are forced out of a thin nozzle and passed between two oppositely charged metal plates. These droplets are attracted to the plate with an opposite charge and repelled by the plate with a similar charge, causing them to deflect as they pass between the plates. By controlling the size and the direction of the voltage applied on the plates, each droplet can be deflected to a particular place on the paper. Many dots like this produce printed characters

Question 17

How does electrostatic painting work to paint a bicycle

Answer 17

The metal spray and the bicycle frame are given opposite charges, where one is positive and the other is negative. As droplets leave the spray gun and approach the bicycle frame, they repel each other and spread out due to the fact that they have the same charge. This results in the formation of a fine spray. Further, because of the opposite charge between the bicycle frame and the droplets, they attract each other and the droplets manage to stick to the bicycle

Question 18

How do electrostatic precipitators

Answer 18

As smoke particles pass through a mesh of wires, they gain a negative charge. The smoke is then passed through another plate that is positively charged. This leads to the charged particles being attracted and sticking onto the large plates, resulting in cleaner smoke being released to the atmosphere, while dust and ash is left behind

Question 19

Why does lightning occur

Answer 19

Due to the low temperature inside the clouds, ice forms, causing ice particles to bump into each other and resulting in separation of charges occurring . The positive charges go to the top of the cloud, while the negative charges are at the bottom of the cloud. These negative charges induce positive charges in the ground by repelling electrons. If the potential difference gets big enough, a spark will jump