16 static electricity

Question 1

Charging

Rubbing

Answer 1

1. Certain amount of electrons are transferred from material to material.
2. Hence, 2nd material becomes negative.
3. As 1st material lost the same amount of electrons, it becomes positively-charged.

Question 2

Charging

Induction

Answer 2

1. Insulated spheres are placed touching each other.
2. Charged rod is brought near one sphere. Electrons are repelled/ attracted to the rod. Negative/ positive charged move onto the other sphere.
3. 2nd sphere is separated from 1st sphere while charged rod is kept in place.
4. Charged rod is removed. Both spheres possess equal amount of opposite charges. 1st sphere is positively/ negatively-charged. 2nd sphere is negatively-positively charged.

Question 3

Negative Charging

Earthing

Answer 3

1. Charged rod is brought near a neutral conductor.
2. Electrons are attracted to the rod and opposite charges remain at the other side.
3. Conductor is earthed. Electrons flow from Earth to the conductor, neutralising the positive charge on the other side.
4. Earthing equipment is removed.
5. Negative charge is redistributed.

Question 4

Definition

Electric Field

Answer 4

A region in which an electric charge experiences a force.

Question 5

Definition

Electric Field Lines

Answer 5

The path a positive charge would take if its free to move.

Question 6

Applications

Photocopier

Answer 6

1. The whole surface of the drum is positively-charged by rotating it near a highly-charged metal wire.
2. When the page is photocopied, light is reflected off the page. The white parts of the page reflect light into some parts of the drum and those areas on the drum lose the positive-charged. As black does not reflect light, those areas that correspond to the black areas remains insulated and remains positively-charged.
3. Toner particles are attracted to the positively-charged areas of the drum.
4. The toner is transferred onto the paper as the drum rotates and presses against it. Heat is supplied to melt the toner power and thus fixing it into the paper.

Question 7

Applications

Laser Printing

Answer 7

1.

Question 8

Applications

Electrostatic Spray Painting

Question 9

Applications

Electrostatic Precipitator

Question 10

Positive Charging

Earthing

Answer 10

1. Charged rod is brought near a neutral conductor.
2. Electrons are repelled from the rod and opposite charges remain at the other side.
3. Conductor is earthed. Electrons flow from conductor to the Earth.
4. Earthing equipment is removed.
5. Positive charge is redistributed.