Question 1: Explain in your own words what the electromagnetic spectrum is and list the main types of waves it includes from longest to shortest wavelength.

Answer: The electromagnetic spectrum is the range of all types of electromagnetic radiation, which includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. From longest to shortest wavelength: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.

Question 2: Describe the main difference between radio waves and gamma rays in terms of wavelength and energy.

Answer: Radio waves have very long wavelengths and low energy, whereas gamma rays have very short wavelengths and high energy.

Question 1: What property of electromagnetic waves remains constant as they travel through a vacuum?

Answer: The speed of electromagnetic waves remains constant at approximately 3.00 x 10^8 metres per second.

Question 2: Explain how the energy of an electromagnetic wave is related to its frequency.

Answer: The energy of an electromagnetic wave is directly proportional to its frequency, as described by the equation E = hf, where E is energy, h is Planck's constant, and f is frequency.

Question 1: Calculate the wavelength of a gamma ray with a frequency of 5 x 10^19 Hz. Use the formula: wavelength = speed of light / frequency. (Speed of light = 3.00 x 10^8 m/s)

Answer: Wavelength = 3.00 x 10^8 m/s / 5 x 10^19 Hz = 6 x 10^-12 metres

Question 2: A microwave has a wavelength of 12 cm. What is its frequency? Use the formula: frequency = speed of light / wavelength. (Speed of light = 3.00 x 10^8 m/s).

Answer: Wavelength = 0.12 m; Frequency = 3.00 x 10^8 m/s / 0.12 m = 2.5 x 10^9 Hz

Question 1: Describe a safety precaution that must be taken when working with X-rays in a laboratory setting.

Answer: One safety precaution is to wear lead shielding or aprons to protect against harmful ionising radiation.

Question 2: Identify one practical use of radio waves in everyday technology and explain how they are utilised.

Answer: Radio waves are used in radio broadcasting to transmit audio signals over long distances.

Question 1: A certain ultraviolet wave has a wavelength of 300 nm. Calculate its frequency. (Speed of light = 3.00 x 10^8 m/s; 1 nm = 1 x 10^-9 m).

Answer: Wavelength = 300 nm = 3.00 x 10^-7 m; Frequency = 3.00 x 10^8 m/s / 3.00 x 10^-7 m = 1 x 10^15 Hz

Question 2: A medical X-ray has an energy of approximately 150 keV. Calculate its frequency, given that 1 eV = 1.602 x 10^-19 J. Use E = hf to find the frequency.

Answer: E = 150 keV = 150 x 10^3 eV = 2.403 x 10^-14 J; Frequency = E / h = 2.403 x 10^-14 J / 6.626 x 10^-34 Js ≈ 3.62 x 10^19 Hz

Question 1: Explain how ultraviolet light is used in sterilisation processes and mention one safety concern associated with its use.

Answer: Ultraviolet light is used in sterilisation because it can kill bacteria and viruses by damaging their DNA. A safety concern is that overexposure can cause skin burns and eye damage.

Question 2: Describe a technological application that uses infrared radiation and discuss its importance in modern industry.

Answer: Infrared radiation is used in remote controls for electronic devices, allowing wireless operation. It is important for convenience and automation in modern technology.