3.3

Question 1

What is a potential difference?

Answer 1

Two differently charged points

Question 2

What is a coulomb (C)?

Answer 2

6.24 x 10 ^ 18 electrons
+
C = 1As (1 ampere-second)

Question 3

What is the formula for Voltage?

Answer 3

V = IR

Question 4

What is the formula for charge?

Answer 4

Q = I(current) x t (time)

Question 5

What is the symbol for charge?

Answer 5

Q

Question 6

Mobile positive charges are found in…?

Answer 6

Liquids and Gases

Question 7

The direction of electrons flowing in a conductor depends on what?

Answer 7

The polarity of the applied voltage

Question 8

What is electrolysis?

Answer 8

The decomposition of chemical compounds by passing an electric current through a liquid

Question 9

A DC current will decompose water into Hydrogen and Oxygen. Which poles will you find each of these?

Answer 9

Negative: Hydrogen
Positive: Oxygen

Question 10

The application of gases can be found in filament bulbs with a higher electrical output of what?

Answer 10

> 60W

Question 11

What gases do high-capacity lamps use?

Answer 11

Halogens = Iodine or Bromine

Question 12

What is the electron beam tube/Braun tube also known as?

Answer 12

The electron gun

Question 13

Which one is the positive and which one is negative when referring to a cathode and anode?

Answer 13

Cathode: Negative
Anode: Positive

Question 14

What is direct current?

Answer 14

When the direction and charge flowing is constant

Question 15

What is the EMF?

Answer 15

Electromotive force (voltage)

Question 16

If the current remains constant in a conductor, what remains the same?

Answer 16

The amount of electrons flowing per second regardless of its cross-sectional area

Question 17

A current which periodically changes its flow direction is called what?

Answer 17

Alternating Current (A/C)

Question 18

What is not a conductor in its pure form?

Answer 18

Water

Question 19

In order to protect the filament from burning in light bulbs, what gases can be used?

Answer 19

Nitrogen, argon or krypton

Question 20

What is an example of using electron current in a vacuum?

Answer 20

Oscilloscopes and Oscillographs

Question 21

What is the definition of direct current?

Answer 21

When the direction and the amount of charge flowing is constant.

Question 22

What is a closed circuit?

Answer 22

A complete circuit with no breaks

Question 23

What is an open circuit?

Answer 23

A circuit that is broken and not complete

Question 24

What is a CRT?

Answer 24

Cathode Ray Tube

Question 25

Why is the electron beam oscilloscope mainly used today?

Answer 25

Because it’s versatile, easy to operate and shock-resistant

Question 26

If not specified, which way does current always flow?

Answer 26

From positive to negative (conventional current)

Question 27

When does an electrical voltage occur?

Answer 27

When there is a deficiency of electrons at one point and an excess of electrons in another point.

Question 28

How can you generate a voltage?

Answer 28

By separating positive and negative charges

Question 29

What is electrical charge?

Answer 29

The sum of billions of electrons and charges involved in every electrical process. The quantity of electricity.

Question 30

In metals, only negative charges move. Which way would the electron flow occur?

Answer 30

In metals, electrons always move in the opposite to the conventional current flow. They would flow from negative to positive

Question 31

What is conventional current flow?

Answer 31

The direction of movement of positive charges. (Positive to negative)

Question 33

Which gases are used inside fluorescent tubes?

Answer 33

Neon and helium

Question 34

Oscillographs provide what?

Answer 34

Rapidly varying processes which can be permanently recorded.

Question 35

Oscilloscopes provide what?

Answer 35

Rapidly varying electrical processes which can be visualised but not recorded.

Question 36

What is the electron beam tube also known as?

Answer 36

Braun tube

Question 37

How does a Braun tube work?

Answer 37

An evacuated glass bulb with a cathode on one side and an anode on the opposite side. Cathode is heated, electrons released and emitted. Attracted to and accelerate towards the anode.

Question 38

What happens inside fluorescent tubes?

Answer 38

Heat causes the molecules of the helium or neon to move in random layers. Electrons of few atoms are split up by external energy supply. Freely moving ions are generated.

Question 39

What is electrical current?

Answer 39

A flow or movement of electrons in one direction caused by a voltage, and will follow conventional current flow. It will flow in a closed path.

Question 40

What is voltage?

Answer 40

The difference between two electrically charged points. Having a potential difference. Also know as EMF. Exerts a force on electrons causing them to move.