Question 1: Explain in your own words how electromagnetic waves are used to transmit information wirelessly.

Answer: Electromagnetic waves carry information by modulating their properties, such as amplitude, frequency, or phase, allowing data to be transmitted over distances without physical cables.

Question 2: List four different types of electromagnetic waves used in communication technologies.

Answer: Radio waves, microwaves, infrared, visible light.

Question 3: Define the term 'modulation' in the context of wireless communication.

Answer: Modulation is the process of varying a wave's properties, such as amplitude, frequency, or phase, to encode information for transmission.

Question 1: Describe the basic mechanism by which a Wi-Fi router transmits data to devices.

Answer: A Wi-Fi router transmits data using radio waves that are modulated with the information signal; devices receive these waves and demodulate them to retrieve the data.

Question 2: Identify two safety precautions that should be considered when working with microwave communication devices.

Answer: Avoid exposure to high microwave radiation and ensure proper shielding and safety distances to prevent burns or health hazards.

Question 3: Which part of the electromagnetic spectrum is most commonly used in satellite television broadcasting?

Answer: Microwaves

Question 1: A microwave communication system operates at a frequency of 10 GHz. Calculate the wavelength of the microwaves used. (Use the speed of light, c = 3 x 10^8 m/s).

Answer: Wavelength λ = c / f = (3 x 10^8 m/s) / (10 x 10^9 Hz) = 0.03 meters or 3 centimetres.

Question 2: A communication device uses infrared light with a wavelength of 900 nm. Explain why infrared is suitable for short-range communication but not for long-distance transmission.

Answer: Infrared waves have a relatively short wavelength and are absorbed or scattered more easily over long distances, making them suitable for short-range communication but less effective for long-distance transmission.

Question 1: Describe how fibre-optic cables use visible light for communication and mention two advantages of this technology over traditional metal cables.

Answer: Fibre-optic cables transmit data through pulses of visible or infrared light within thin strands of glass or plastic. Advantages include higher data transmission rates and immunity to electromagnetic interference compared to metal cables.

Question 2: Identify a modern technology that uses the electromagnetic spectrum for communication and explain its significance in everyday life.

Answer: Mobile phones use radio waves for wireless communication, enabling instant connectivity, access to information, and communication globally, which is vital for daily activities.