Unit 1: C3 Use of electromagnetic waves in communication

Question 1

How do electromagnetic waves travel in a vacuum?

Answer 1

All electromagnetic waves travel at the same speed in a vacuum, approximately 3 ×10^8 m/s

Question 2

What is the inverse square law for wave intensity?

Answer 2

The intensity, 𝐼, of a wave is inversely proportional to the square of the distance, 𝑟, from the source:
𝐼 = 𝑘/𝑟^2
where, 𝑘, is a constant.

Question 3

How are electromagnetic waves grouped in the spectrum?

Answer 3

They are grouped by frequency and wavelength, ranging from low-frequency radio waves to high-frequency gamma rays.

Question 4

How are electromagnetic waves used in satellite communication?

Answer 4

Satellites use microwave frequencies for transmitting and receiving signals, as these can penetrate the atmosphere.

Question 5

How do mobile phones use electromagnetic waves?

Answer 5

Mobile phones use radio waves to transmit and receive voice and data signals over long distances.

Question 6

What is the role of Bluetooth® in communication?

Answer 6

Bluetooth® uses short-wavelength radio waves to enable wireless communication between devices over short distances.

Question 7

How is infrared used in communication?

Answer 7

Infrared waves are used in remote controls and short-range communication, such as data transfer between devices.

Question 8

What is Wi-Fi, and how does it use electromagnetic waves?

Answer 8

Wi-Fi uses radio waves at specific frequencies to provide wireless internet access within a localized area.