Question 1: Explain how radio waves are used in wireless communication systems.

Answer: Radio waves are used in wireless communication because they can travel long distances through the atmosphere and can carry information via modulation of their amplitude, frequency, or phase.

Question 2: List three types of electromagnetic waves used in modern communication technologies.

Answer: Radio waves, microwaves, and infrared waves.

Question 1: Define the term 'wavelength' as it relates to electromagnetic waves.

Answer: Wavelength is the distance between two consecutive points of similar phase in a wave, such as from crest to crest or trough to trough.

Question 2: What is the relationship between frequency and wavelength of an electromagnetic wave?

Answer: Frequency and wavelength are inversely related; as wavelength increases, frequency decreases, and vice versa, according to the formula c = λ × f.

Question 1: Calculate the wavelength of a microwave with a frequency of 2.45 GHz. (Speed of light, c = 3.00 × 10^8 m/s)

Answer: λ = c / f = (3.00 × 10^8 m/s) / (2.45 × 10^9 Hz) ≈ 0.122 m

Question 2: A radio station broadcasts at a frequency of 100 MHz. What is the wavelength of the radio wave?

Answer: λ = (3.00 × 10^8 m/s) / (1.00 × 10^8 Hz) = 3.00 m

Question 1: Describe a simple experiment to demonstrate how different frequencies of electromagnetic waves are used in communication devices.

Answer: One possible experiment involves using a set of antennas and wave generators to produce various frequencies of EM waves. Students observe how different frequencies penetrate materials or are absorbed, illustrating their use in communication. Safety precautions include avoiding exposure to high-power EM waves and ensuring proper shielding.

Question 1: A satellite transmits signals at a frequency of 12 GHz. The received signal has an energy of approximately 7.9 × 10^-24 Joules. Calculate the approximate wavelength of the transmitted wave.

Answer: Using E = h × f, where h = 6.626 × 10^-34 Js, f = 12 × 10^9 Hz, E ≈ 7.97 × 10^-24 J. Wavelength λ = c / f = (3.00 × 10^8 m/s) / (12 × 10^9 Hz) ≈ 0.025 m.

Question 2: Explain how the frequency of an electromagnetic wave affects its use in communication technologies such as mobile phones and satellite links.

Answer: Higher frequency waves, like microwaves, can carry more data and are suitable for satellite communications and mobile phones. Lower frequency waves, like radio waves, travel longer distances and are used for AM/FM radio broadcasting.

Question 1: Identify two advantages and one disadvantage of using infrared waves in remote controls.

Answer: Advantages: They are inexpensive and do not interfere with radio signals. Disadvantage: They require line-of-sight and can be blocked by obstacles.

Question 2: Describe how fibre optic cables use EM waves for communication and mention one safety consideration during installation.

Answer: Fibre optic cables use pulses of infrared light (a form of EM wave) transmitted through thin strands of glass or plastic to carry data at high speeds. Safety considerations include avoiding eye exposure to the intense light sources during installation and handling the delicate fibres carefully to prevent breakage.