# Waves and Communication

In this worksheet, students will examine the properties of different types of waves and how they are used to aid communication.

Key stage:  KS 4

Curriculum topic:  Physics: Wave Motion

Curriculum subtopic:  Uses and Hazardous Effects

Difficulty level:

### QUESTION 1 of 10

The diagram below shows the Electromagnetic Spectrum:

Radiowaveslight and microwaves are part of this family of waves. They are used for heating and cooking food, but they are also used in communication technology.

Microwaves are used for mobile phones, satellite TV and long distance communication. Microwave aerials are on high buildings, because transmitters and receivers have to be in 'line of sight'.

Satellite dishes are microwave receivers that deliver satellite television channels.

Satellites orbiting the Earth are in line of sight with a huge aerial on the ground, which handles a great number of phone calls and television pictures at the same time.

Many people worry about the position of aerials and the excessive use of mobile phones, due to concerns about the possible risk of cancer. Young people who are still developing are at higher risk of being affected. Microwave signals can interfere with medical equipment and they must be switched off in hospitals.

Infrared signals are used to make remote controls, wireless computer mice and security alarm sensors work. Signals emitted by remote controls are digital signals, which only have two values (on and off) and that can minimise the effect of interference.

Radiowaves are also useful for wireless technology and the radio. They are reflected off solid surfaces, so sometimes provide signals in hard to reach areas.

Light has many uses, including communication, and can be sent with just a torch. This type of signal needs to be decoded. Sound is not part of the Electromagnetic Spectrum, but it is still a wave and widely used in communication. Humans and other animals can communicate using sound.

Waves have some properties: amplitudewavelengthfrequency and speed. Study the diagram as some questions will be about the properties of waves. The speed of a wave is calculated using the following formula:

wave speed = frequency x wavelength

What is the Electromagnetic Spectrum?

A series of visible light rays

A long colourful strip

A family of waves

Tick two types of waves that are used in communication.

X waves

Sea waves

Microwaves

What sends a microwave signal?

A transmitter

A laser

Intaker

Collector

What is the appropriate position of transmitters and receivers?

In line

In line of sound

In line of sight

What are the dangers of heavy mobile phone use and aerials built near populated areas?

Increased risk of cancer

Increased risk of heart disease

Increased risk of communication problems

What type of signals are emitted by remote controls?

Digital

Gamma rays

Morse code

What effect does this type of signal minimise?

Interruption

Intervention

Interference

How would you define the frequency of a wave?

The number of waves

The number of crests or troughs of a wave that pass through a specific point in one second

The number of crests of a wave

How would you define wavelength?

The distance between two identical points of a wave

The distance between a crest and trough of a wave

The difference between the highest and lowest point of a wave

• Question 1

What is the Electromagnetic Spectrum?

A family of waves
EDDIE SAYS
The Electromagnetic Spectrum is a family of waves.
• Question 2

Tick two types of waves that are used in communication.

Microwaves
EDDIE SAYS
Radio-waves and microwaves are used in communication. Radiowaves for, well, radio... and microwaves for mobile phones and TV.
• Question 3

What sends a microwave signal?

A transmitter
EDDIE SAYS
Transmitters send microwave signals. but not just Microwaves- they send any type of wave. You could say that they TRANSMIT the waves.
• Question 4

EDDIE SAYS
A receiver receives microwave signals. The clue is in the name, people.
• Question 5

What is the appropriate position of transmitters and receivers?

In line of sight
EDDIE SAYS
Transmitters and receivers have to be in line of sight. If you think about visible light, these are all on the same family - so if they can't 'see' each other, then they are not going to be able to get their signal!
• Question 6

What are the dangers of heavy mobile phone use and aerials built near populated areas?

Increased risk of cancer
EDDIE SAYS
The dangers of heavy mobile phone use and aerials built near populated areas is an increased risk of cancer. However, this risk is VERY small with a lot of studies showing that there is no link.
• Question 7

What type of signals are emitted by remote controls?

Digital
EDDIE SAYS
Remote controls emit digital signals. This is because they work with computers (your TV is a small computer). Anything that uses computers needs to use digital.
• Question 8

What effect does this type of signal minimise?

Interference
EDDIE SAYS
Digital signals minimise interference because the signal can only be on or off. this means that there is much less confusion about what the signal is trying to say.
• Question 9

How would you define the frequency of a wave?

The number of crests or troughs of a wave that pass through a specific point in one second
EDDIE SAYS
Do not worry if you did not know the answer to this question; it was meant to make you think scientifically. Wave frequency is the number of crests or troughs of a wave that pass through a specific point in one second.
• Question 10

How would you define wavelength?

The distance between two identical points of a wave
EDDIE SAYS
Wavelength is the distance between two identical points of a wave; it could be between two crests or two troughs. Half the difference between the highest and lowest point of a wave is the definition of amplitude.
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