# Electrostatics and Current Flashcards

1
Q

When two insulating materials are rubbed together, what particle could be transferred between them?

A

An electron would transfer from one insulator to the other.

2
Q

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

A

an insulator such as plastic or wood

3
Q

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

A

Nanocoulombmeter becomes negatively charged

Explanation

Polythene gains electron from the cloth to become negatively charged

This negative charge transfers to the nanocoulombmeter when electrons transfer from the rod to the nanocoulombmeter

4
Q

What is the current if 7200 C passes in 1 hour ?

A

I = Q/t

I = 7200 C/ (1 x 60 x 60) s

I = 7200 C/ 3600 s

I = 2 A

time must be in seconds!

5
Q

What is the current if 360 C passes in 2 min?

A

I = Q/t

I = 360 C/ (2 x 60) s

I = 360 C / 120s

I = 3 A

6
Q

Name three uses of electrostatics

A
1. electrostatic smoke removal from chimneys
2. photocopier
3. inkjet printer
4. electrostatic paint sprayer
5. electrostatic crop sprayer
7
Q

Where are neutrons located in an atom?

A

the nucleus

8
Q

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

A
• 3 nC
9
Q

Describe what a gold leaf electroscope is.

A

A gold leaf electroscope is used to study electrostatic charge

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

10
Q

What is an induced charge?

A

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

11
Q

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

A

They would repel because like charges repel

12
Q

What is the current if 100 C passes in 200s ?

A

I = Q/t

I = 100 C/ 200 s

I = 0.5 A

13
Q

What does the prefix nano stand for in 10 nC

A

nano is 10-9 or 10nC = 10 x 10-9 C

14
Q

What is the definition for current?

A

The rate of flow of charge

OR

The number of coulombs passing a point in a circuit per unit time

15
Q

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

A

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.

16
Q

If 10 mA flows for 10 minutes, how much charge flows?

A

Q = I x t

Q = 0.01 A x (10 x 60s ) = 6C

time must always be converted into seconds

current must be in amps so milli is 10-3

17
Q

What is the current if 360 C passes in 2 min?

A

I = Q/t

I = 360 C/ (2 x 60) s

I = 360 C / 120s

I = 3 A

18
Q

What is the current if 100 C passes in 200s ?

A

I = Q/t

I = 100 C/ 200 s

I = 0.5 A

19
Q

A negatively charge polythene rod is scrapped across a gold leaf electroscope. The gold leaf rises.

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

A

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 negative and negative repel the same as positive and positive charges.

20
Q

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

A

Nanocoulombmeter becomes negatively charged

Explanation

Polythene gains electron from the cloth to become negatively charged

This negative charge transfers to the nanocoulombmeter when electrons transfer from the rod to the nanocoulombmeter

21
Q

What does the prefix micro stand for in 100 uA

A

micro is 10-6 or 100 uC = 100 x 10-6 C

22
Q

Explain how a gold leaf electroscope works.

A

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.

23
Q

What is the symbol for an ammeter and how is it connected in the circuit?

A

An ammeter is connected in series

24
Q

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

A

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.

25
Q

What does the prefix micro stand for in 100 uA

A

micro is 10-6 or 100 uC = 100 x 10-6 C

26
Q

What does the prefix milli stand for in 65 mA

A

milli is 10-3 or 65 mC = 65 x 10-3 C

27
Q

What does the prefix nano stand for in 10 nC

A

nano is 10-9 or 10nC = 10 x 10-9 C

28
Q

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

A

The would repel because like charges repel

29
Q

If 100 A flows for 10 s, how much charge passes?

A

Q= I x t

Q = 100 A x 10 s = 1000 C

30
Q

What is the current if 10 nC passes in 5 s ?

A

I = Q/t

I = 10 nC/ 5 s

I = 2 nA

31
Q

What equation links charge, current and time?

A

Charge = current x time OR Current = charge / time

32
Q

I am the rate of flow of charge. What am I?

A

Current

33
Q

560 uA

is

560 x10-3 A

560 000 000 A

0.560 A

OR

0.000 560 A

A

560 uA

560x 10-6 A

which

is

0.000 560 A

34
Q

If 4 A flows for 2 minutes, how much charge flows?

A

Q = I x t

Q = 4 A x (2 x 60s ) = 480C

time must always be converted into seconds

35
Q

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

A

The would repel because like charges repel

36
Q

What is the current if 1000 C passes in 500s?

A

I = Q/t

I = 1000 C/ 500 s

I = 10C / 5s

I = 2 A

37
Q

Where are protons located in an atom?

A

the nucleus

38
Q

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

A

Electrons transfer from the cloth to the rod.

The polythene rod becomes negatively charged

The cloth becomes postively charged

39
Q

What sort of material will allow charge to flow through it?

A

conductor such as a metal

40
Q

What is the relative charge of an electron?

A

-1

41
Q

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

A

+ 5 nC

42
Q

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

A

The would repel because like charges repel

43
Q

How can a charged object be discharged?

A

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

44
Q

What is the relative charge of a proton?

A

+1

45
Q

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

A

Electrons transfer from the cloth to the rod.

The polythene rod becomes negatively charged

The cloth becomes postively charged

46
Q

What is the relative charge of neutron?

A

0

47
Q

What is the current if 10 nC passes in 5 s ?

A

I = Q/t

I = 10 nC/ 5 s

I = 2 nA

48
Q

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

A

Electrons transfer from the rod to the cloth.

The acetate rod becomes positively charged

The cloth becomes negatively charged

49
Q

If 4 A flows for 2 minutes, how much charge flows?

A

Q = I x t

Q = 4 A x (2 x 60s ) = 480C

time must always be converted into seconds

50
Q

Where are electrons located in an atom?

A

shells

51
Q

What equation links current, charge and time?

A

Current = charge / time OR Charge = current x time

52
Q

What is the current if 1000 C passes in 500s?

A

I = Q/t

I = 1000 C/ 500 s

I = 10C / 5s

I = 2 A

53
Q

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

A

+ 5 nC

54
Q

Name three dangers of electrostatic charge

A
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
55
Q

What can we use to measure charge?

A

A nanocoulombmeter

56
Q

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

A

Move them further apart OR decrease their charge.

57
Q

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

A

The would attract because unlike charges repel