Topic 10 + 11

Question 1

What are atoms?

Answer 1

Atoms are building blocks of all matter

Question 2

What is the nucleus made up of?

Answer 2

Protons + neutrons

Question 3

Where is all the mass of the atom?

Answer 3

The nucleus

Question 4

Define proton

Answer 4

Positively charged particles with a relative atomic mass of one unit

Question 5

Define neutrons

Answer 5

No charge, also with a relative mass of one unit

Question 6

Define electrons

Answer 6

Negative charge with mass of 1/2000

Question 7

Function of cell/battery

Answer 7

Provides circuit with a source of potential difference

Question 8

Function of switch

Answer 8

Turn circuit on (closed), or off (open)

Question 9

Function of fixed resistor

Answer 9

A resistor limits the flow of current. A fixed resistor has a resistance it cannot change

Question 10

Function of variable resistor

Answer 10

A resistor with a slide that can be used to change its resistance. Us usually used in dimmer switches and volume controls

Question 11

Function of thermistor

Answer 11

The resistance of a thermistor depends on its temperature. As its temperature increases, it’s resistance decreases

Question 12

Function of light-dependent resistor (LDR)

Answer 12

The resistance of an LRD depends on the light intensity. As its light intensity increases, its resistance decreases

Question 13

Function of motor

Answer 13

A device that converts electrical energy to mechanical energy

Question 14

Function of diode

Answer 14

A diode allows current to flow in one direction only. Used to convert AC to DC current

Question 15

Function of ammeter

Answer 15

Used to measure current in a circuit. Connected in series with other components

Question 16

Function of light-emitting diode (LED)

Answer 16

equivalent to a diode, emits light when a current passes through it. Used for aviation lighting and displays.

Question 17

Function of voltmeter

Answer 17

Use dot measure potential difference of an electrical component. Connected in parallel with relevant component

Question 18

Define potential difference

Answer 18

The amount of energy transferred per unit of charge passing through the terminals

Question 19

Equation of potential difference

Answer 19

V (v) = E (j) / Q (c)

Question 20

Define electric current

Answer 20

The rate of flow charge, the amount of charge passing through a component per second

Question 21

Equation linking current, charge + time

Answer 21

I (A) = Q (C) / t (s)

Question 22

What are wires in an electric circuit made of and why?

Answer 22

Made of metal because it is good conductor of electric current

Question 23

What is the current in wires?

Answer 23

The current is a flow of electrons in wires

Question 24

A current will flow in a circuit if:

Answer 24

• the circuit includes a source of potential difference

- circuit is closed

Question 25

Name 3 sources of potential difference

Answer 25

- cell - batteries - Electrical generator

Question 26

What is the value of current at any point in a series circuit and why?

Answer 26

Same value at any point in series circuit because the number of electrons per second that passes through one part of the circuit is the same number that passes through any other part

Question 27

Define junction in circuit

Answer 27

Where two or more wires meet

Question 28

Explain what it means when current is conserved

Answer 28

This means the amount of current flowing into the junction is equal to the amount of current flowing out

Question 29

Why is current conserved?

Answer 29

Because charge is conserved

Question 30

Define conventional current

Answer 30

The flow of positive charge from the positive terminal of a cell to the negative terminal

Question 31

What are the two types of resistors?

Answer 31

Fixed resistors | Variable resistors