S3 - Physics Test (3)

Question 1

What are the 3 stages of an electronic system?

Answer 1

Input ~> Process ~> Output

Question 2

What does the ‘input’ device do?

Answer 2

Change different forms of energy into electrical energy

Question 3

What does the ‘output’ device do?

Answer 3

Change electrical energy into another form of energy

Question 4

What do magnets have that affect the space around it?

Answer 4

A magnetic field

Question 5

How can we see magnet fields?

Answer 5

By sprinkling iron filings beside a magnet

Question 6

How can we draw magnetic fields?

Answer 6

By drawing lines with an arrow pointing to the south, from the north

Question 7

What happens when a current flows in a wire?

Answer 7

A magnetic field is created around it

Question 8

What is an electromagnet?

Answer 8

Wire wrapped around an iron core

Question 9

What happens when a current flows through the wire of an electromagnet?

Answer 9

The core is magnetised

Question 10

What is a transformer?

Answer 10

A device which can alter the size of an A.C voltage

Question 11

How do we work out the relation between the voltage and number of turns in a transformer?

Answer 11

Np Vp
— = —
Ns Vs

Question 12

What is the lowest possible temperature and what is it called?

Answer 12

-273°C

Absolute zero

Question 13

Where does the Kelvin temperature scale start?

Answer 13

Absolute zero / -273°C

Question 14

How to we convert °C and K?

Answer 14

Adding/subtracting 273

Question 15

What are the energy changes of the following:

• Motor
• Lamp
• Buzzer

Answer 15

Motor: Electrical to Kinetic
Lamp: Electrical to light (and heat)
Buzzer: Electrical to sound

Question 16

What might be possible, everyday, applications for the following:
- Motor
- Lamp
- Buzzer

Answer 16

• A fan
• A security light
• A smoke alarm

Question 17

Digital signals are often processed using…

Answer 17

Logic gates

Question 18

What name is given to ‘on’ and ‘off’ signals?
What voltage do these signals have?

Answer 18

On: high - a ‘non-zero voltage’
Off: low - a ‘zero voltage’

Question 19

How many inputs and outputs do NOT gates have?

Answer 19

Inputs: 1
Outputs: 1

Question 20

How many inputs and outputs do AND gates have?

Answer 20

Inputs: 2
Outputs: 1

Question 21

How many inputs and outputs do OR gates have?

Answer 21

Inputs: 2
Outputs: 1

Question 22

What will the output in a NOT gate be compared to its input?

When do we need to know this information?

Answer 22

• The opposite
• When filling out truth tables

Question 23

What will the output in an AND gate be compared to its input?

When do we need to know this information?

Answer 23

• Low, if both inputs aren’t high
• When filling out truth tables

Question 24

What will the output in an OR gate be compared to its input?

When do we need to know this information?

Answer 24

• Only high if either input or both inputs are high
• When filling out truth tables

Question 25

What are the stages of a fossil fuel power station?

Answer 25

• Fossil fuel is burned: produces heat
• Heat changes water into steam in the boiler
• Steam turns the turbines
• Turbines turn the generator to produce electricity

Question 26

What are the energy changes of a fossil fuel power station?

Answer 26

Chemical energy ~> heat energy ~> kinetic energy ~> electrical energy

Question 27

What could be some applications of electromagnets and how do they work?

Answer 27

• In a relay
• Switch 1 is closed, current passes through the coil, magnetises the relay, attracts and closes switch 2, allowing the current to flow and run the motor.
• In a bell
• The switch is closed, the electromagnet is magnetised, attracting the iron and hitting the hammer on the gong, when the hammer moves it breaks the circuit and is pulled back by the spring.

Question 28

What will happen to a wire if it is moving in a magnetic field?

Answer 28

The voltage of the wire will be induced

Question 29

What factors affect the size of an induced voltage?

Answer 29

• The strength of a magnet
• The number of turns on the coil
• Speed of the magnet or coil