Question 1: Define the electromagnetic spectrum and explain its relevance to modern communication.

Answer: The electromagnetic spectrum includes all types of electromagnetic radiation, from radio waves to gamma rays. It is crucial for communication because different wavelengths are used for broadcasting, mobile phones, satellite communication, and more, due to their varying properties like wavelength, frequency, and energy.

Question 2: List three types of electromagnetic waves used in communication and specify their typical wavelength ranges.

Answer: Radio waves (1 mm to 100 km), Microwaves (1 mm to 1 m), Infrared waves (700 nm to 1 mm).

Question 3: Explain how radio waves are used in television broadcasting.

Answer: Radio waves carry television signals from broadcasting stations to receivers. They transmit audio and video information over large distances, allowing TVs to receive signals via antennas or satellite dishes.

Question 4: What is the relationship between wavelength and frequency of electromagnetic waves? (Write the formula.)

Answer: Speed of light = wavelength × frequency, or c = λ × f.

Question 5: Calculate the frequency of an electromagnetic wave with a wavelength of 0.5 meters. (Use c = 3.00 × 10^8 m/s)

Answer: f = c / λ = (3.00 × 10^8 m/s) / 0.5 m = 6.00 × 10^8 Hz

Question 6: Describe one safety consideration when working with microwave communication devices.

Answer: Microwave devices emit high-frequency radiation that can cause burns or tissue damage; therefore, safety precautions include avoiding direct exposure and using shielding.

Question 7: Identify which part of the EM spectrum is most suitable for satellite communication and justify your choice in terms of wavelength and atmospheric interference.

Answer: Microwaves are most suitable for satellite communication because their wavelengths can penetrate Earth's atmosphere effectively, and they experience less atmospheric interference compared to higher-frequency waves like infrared or visible light.

Question 8: Which type of electromagnetic wave has the highest energy? Explain briefly.

Answer: Gamma rays have the highest energy because their frequency is the greatest, according to the relation E = h × f, where h is Planck's constant.

Question 9: A mobile phone operates using radio waves with a frequency of approximately 2.4 GHz. Calculate the wavelength of these waves. (Use c = 3.00 × 10^8 m/s)

Answer: λ = c / f = (3.00 × 10^8 m/s) / (2.4 × 10^9 Hz) ≈ 0.125 m

Question 10: Explain the principle behind fibre optic communication and mention one advantage over traditional radio wave communication.

Answer: Fibre optic communication uses pulses of infrared light transmitted through thin glass or plastic fibres. It offers higher data transmission speeds, lower signal loss, and immunity to electromagnetic interference compared to radio wave communication.

Question 11: Describe a practical experiment to demonstrate how different frequencies of electromagnetic waves can be used for communication.

Answer: One possible experiment involves using a set of radio transmitters and receivers operating at different frequencies. Students can observe how each frequency transmits signals over specific distances, demonstrating the importance of wavelength and frequency in communication. Safety precautions include ensuring equipment is used within safe exposure limits and avoiding interference with other devices.