02 Electrostatics

Question 1

When two insulating materials are rubbed together, which particle is transferred between them?

Answer 1

An electron** would **transfer from one insulator to the other.

Question 2

What sort of material does not allow charge to flow through it easily?

Answer 2

an insulator such as plastic or wood

Question 3

A polythene rod is charged by friction and scraped across a nanocoloumbmeter, which charge will the nanocoulombmeter adopt?

Answer 3

Nanocoulombmeter becomes negatively charged

Explanation

Electrons transfer from the cloth to the polythene rod. The rod becomes negatively charged

These electrons transfers from the polythene rod to the nanocoulombmeter

Question 4

Name three uses of electrostatics

Answer 4

1. electrostatic smoke removal from chimneys
2. photocopier
3. inkjet printer
4. electrostatic paint sprayer

Question 5

Where are neutrons located in an atom?

Answer 5

the nucleus

Question 6

What charge would a rod adopt if 3nC of electrons were transferred from a cloth to the surface of the rod?

Answer 6

(negative) -3 nC

Question 7

Describe what a gold leaf electroscope is.

Answer 7

A gold leaf electroscope is used to study electrostatic charge

It has a metal plate at the top which is connected to a metal post encased in a glass box. A piece of very thin gold foil is glued to the side of the metal post.

When charged- the metal rod and gold leaf have the same charge and repel, gold leaf moves up.

Question 8

What is an induced charge?

Answer 8

When a neutral object has a separation of charge within itself.

Electrons move from one side of the object to the other.

The side with more electrons is negatively charged

The side with fewer electrons is positively charged.

Overall the charge is neutral- charge is only displaced within the object itself

Question 9

What would happen if two negatively charge balloons were hung side by side?

Answer 9

They would repel because like charges repel

Question 10

What does the prefix nano stand for in 10 nC

Answer 10

nano is 10^-9

or

10nC = 10 x 10^-9 C

Question 11

Explain why only electrons are transferred when objects are charged by friction.

Answer 11

Electrons are located in the outer shells of an atom and are easily removed.

However, protons are located in the nucleus at the centre of the atom and are tightly bound.

Question 12

A negatively charged polythene rod is scraped across a gold leaf electroscope. The gold leaf rises.

What would you observe if the same thing was done with an acetate rod?

Answer 12

The gold leaf would rise just the same as it did with the polythene rod.

The gold foil is repelled from the central post in both cases as both the post and the gold leaf have the same charge.

Question 13

A polythene rod is charged by friction and scraped across a nanocoloumbmeter, what charge will the nanocoulombmeter adopt?

Answer 13

Nanocoulombmeter becomes negatively charged

Explanation

Polythene gains electrons from the cloth to become negatively charged

The electrons transfers from the polythene rod to the nanocoulombmeter

Question 14

What does the prefix micro stand for in 100 uA

Answer 14

micro is 10^-6

or 1

00 uC = 100 x 10^-6 C

Question 15

Explain how a gold leaf electroscope works.

Answer 15

When it is charged, both the rod and leaf adopt the same charge and the gold leaf is repelled from the rod and rises.

The greater the charge, the greater the repulsion the further the gold foil rises.

Question 16

A acetate rod is charged by friction and scraped across a nanocoloumbmeter, what charge will the nanocoulombmeter adopt?

Answer 16

Nanocoulombmeter becomes positively charged

Explanation

Acetate loses electron to the cloth to become positively charged

Electrons transfer from the nanocoulombmeter to the rod, leaving the nanocoulombmeter positive.

Question 17

What does the prefix milli stand for in 65 mA

Answer 17

milli is 10^-3

or

65 mC = 65 x 10^-3 C

Question 18

Where are protons located in an atom?

Answer 18

the nucleus

Question 19

A polythene rod is rubbed with a cloth. What happens?

Answer 19

Electrons transfer from the cloth to the rod.

The polythene rod becomes negatively charged

The cloth becomes postively charged

Question 20

Which sort of material allows charge to flow through it?

Answer 20

a conductor such as a metal

Question 21

What is the relative charge of an electron?

Answer 21

-1

Question 22

What charge would a rod adopt if 5nC of electrons were transferred from its surface to a cloth?

Answer 22

+ 5 nC

Question 23

What would happen if two positively charge rods were hung side by side?

Answer 23

The would repel because like charges repel

Question 24

How can a charged object be discharged?

Answer 24

Earth it. Connect a wire conductor from the object to a stake in the ground.

Question 25

What is the relative charge of a proton?

Answer 25

+1

Question 26

What is the relative charge of neutron?

Answer 26

0

Question 27

An acetate rod is rubbed with a cloth. What happens?

Answer 27

Electrons transfer from the rod to the cloth.

The acetate rod becomes positively charged

The cloth becomes negatively charged

Question 28

Where are electrons located in an atom?

Answer 28

shells

Question 29

Name three dangers of electrostatic charge

Answer 29

1. Refueling cars or aircraft
2. explosion of dust or fine powder in industry
3. Lightning from charge build up in clouds
4. Spark in operating theatre- explosion of oxygen

Question 30

What can we use to measure charge?

Answer 30

A nanocoulombmeter

Question 31

How can we reduce the electrostatic force acting on the objects below?

Answer 31

Move them further apart OR decrease their charge.

Question 32

What would happen if a negatively charge rod and a positively charge rod were hung side by side?

Answer 32

The would attract because unlike/opposite charges attract