Radio Waves

Question 1

What are electromagnetic (EM) waves made up of and how are they generated?

Answer 1

-EM waves are composed of oscillating electric and magnetic fields
-they are generated by oscillating charges in alternating currents

Question 2

How can radio waves be produced?

Answer 2

by using an alternating current in an electrical circuit

Question 3

what is the object called where charges oscillate to create radio waves?

Answer 3

A transmitter

Question 4

What happens when transmitted radio waves reach a receiver?

Answer 4

1)When transmitted radio waves reach a receiver, they are absorbed by the material of the receiver.
2)The energy carried by the waves is transferred to the electrons in the material of the receiver, causing them to oscillate.
3)If the receiver is part of a complete electrical circuit, it generates an alternating current with the same frequency as the radio wave that generated it.

Question 5

What are radio waves?

Answer 5

Radio waves are electromagnetic radiation with wavelengths longer than about 10 cm

Question 6

Why can long-wave radio signals to be transmitted over long distances?

Answer 6

Long-wave radio signals with wavelengths of 1-10 km can diffract (bend) around the curved surface of the Earth and obstacles, enabling transmission over long distances.

Question 7

What allows radio signals, (particularly short-wave radio signals) to be received over long distances?

Answer 7

Short-wave radio signals (wavelengths of about 10 m - 100 m) can be received at long distances due to reflection from the ionosphere, even if the receiver is not in line of sight of the transmitter

Question 8

What does Bluetooth utilise short-wave radio waves for?

Answer 8

for wireless data transmission between devices over short distances, such as wireless headsets in cars.

Question 9

What is the ionosphere?

Answer 9

An electrically charged layer in the earth’s upper atmosphere

Question 10

What allows short-wave radio signals to be transmitted over long distances?

Answer 10

They can be reflected from the ionosphere

Question 11

Can medium-wave signals reflect from the ionosphere, and what factors affect their ability to do so?

Answer 11

Medium-wave signals (particularly shorter ones) can also reflect from the ionosphere depending on atmospheric conditions and time of day.

Question 12

What is the limitation of radio waves with very short wavelengths in terms of reception?

Answer 12

To get reception you must be in direct sight of the transmitter as the signal doesn’t bend or travel far through buildings