Question 1: Define electromagnetic spectrum and explain why different wavelengths are used for specific applications.

Answer: The electromagnetic spectrum is the range of all types of EM radiation, distinguished by wavelength and frequency. Different wavelengths are used for specific applications because they have unique properties, such as penetration ability, energy levels, and interaction with materials.

Question 1: Which part of the EM spectrum is primarily used in microwave ovens and why?

Answer: Microwaves are used in microwave ovens because their wavelength interacts with water molecules, causing them to vibrate and produce heat efficiently.

Question 2: Explain how ultraviolet (UV) radiation is used in sterilization processes.

Answer: UV radiation destroys bacteria and other microorganisms by damaging their DNA, making it useful for sterilization.

Question 1: Calculate the wavelength of a radio wave with a frequency of 100 MHz. (Speed of light, c = 3.0 x 10^8 m/s).

Answer: Wavelength (λ) = c / f = (3.0 x 10^8 m/s) / (1.0 x 10^8 Hz) = 3.0 meters

Question 2: A UV lamp emits light at a wavelength of 250 nm. Calculate its frequency.

Answer: Frequency (f) = c / λ = (3.0 x 10^8 m/s) / (250 x 10^-9 m) = 1.2 x 10^15 Hz

Question 1: Describe a basic experimental setup to demonstrate how infrared radiation can be detected. Include safety precautions.

Answer: A simple setup involves using an infrared-sensitive detector or a thermopile connected to a voltmeter, with an IR source such as a heat lamp. Safety precautions include avoiding direct eye exposure to IR sources, ensuring proper ventilation, and handling electrical equipment carefully.

Question 1: A certain type of X-ray machine operates at a wavelength of 0.1 nm. Explain its application in medical imaging and why this wavelength is suitable.

Answer: This X-ray machine is used for detailed imaging of bones and tissues because the short wavelength allows it to penetrate soft tissues with minimal absorption, providing clear images of internal structures.

Question 1: Explain how radio waves are used in communication systems. Include the advantages of using radio waves over other types of EM radiation. (6 marks)

Answer: Radio waves are used in communication systems to transmit audio, video, and data signals over long distances due to their ability to travel through the atmosphere with minimal attenuation. They are advantageous because they can penetrate obstacles, require relatively low power for transmission, and can be broadcast over large areas, making them ideal for radio, television, and mobile communication.

Question 1: Identify and explain two industries that rely heavily on electromagnetic waves, describing which parts of the spectrum they use and why.

Answer: The medical industry uses X-rays for imaging due to their short wavelength and high energy, which can penetrate tissues. The telecommunications industry relies on radio and microwave frequencies for wireless communication because they can travel long distances with minimal loss.