Question 1: Explain why ultraviolet (UV) radiation can be harmful to human skin.

Answer: UV radiation can cause skin damage and increase the risk of skin cancer because it can damage DNA in skin cells.

Question 2: Describe one safety precaution that should be taken when working with X-rays in a medical setting.

Answer: Wearing lead aprons and using lead shields to protect parts of the body from exposure.

Question 1: Define ionising radiation and name two types of electromagnetic waves that are ionising.

Answer: Ionising radiation has enough energy to remove electrons from atoms, creating ions. X-rays and gamma rays are two types of ionising EM waves.

Question 2: Explain how gamma rays can damage human cells.

Answer: Gamma rays can penetrate cells and DNA, causing ionisation and mutations, which can lead to cell damage or cancer.

Question 1: Calculate the energy of a gamma photon with a wavelength of 1 x 10^-12 metres using the formula E = hc/λ. (h = 6.626 x 10^-34 Js, c = 3 x 10^8 m/s)

Answer: E = (6.626 x 10^-34 Js)(3 x 10^8 m/s) / (1 x 10^-12 m) = 1.9878 x 10^-13 Joules

Question 2: A dose of UV radiation is considered dangerous if the energy exposure exceeds 10^-3 Joules per square metre. How much energy in Joules is delivered to an area of 2 square metres at this dangerous level?

Answer: Total energy = 10^-3 J/m² x 2 m² = 2 x 10^-3 Joules

Question 1: Identify two safety precautions that should be implemented when handling ultraviolet (UV) lamps in a lab setting.

Answer: Wearing protective goggles and limiting exposure time to prevent skin burns and eye damage.

Question 2: Describe a simple experiment to demonstrate the effect of ionising radiation on living cells, including safety considerations.

Answer: An experiment could involve exposing a sample of bacterial cultures to controlled X-ray doses while wearing adequate shielding and monitoring radiation levels closely. Safety measures include using lead shielding, minimal exposure time, and working behind protective barriers to prevent unnecessary exposure.

Question 1: A medical X-ray exposes a patient to a dose of 0.015 Joules. If the X-ray beam covers an area of 0.005 m², what is the energy per unit area, and is this considered a safe level?

Answer: Energy per unit area = 0.015 J / 0.005 m² = 3 J/m². This exceeds typical safe exposure levels and could pose health risks.

Question 2: In a scenario where exposure to microwave radiation is high, explain the potential health effects and the safety measures that should be taken.

Answer: High microwave exposure can cause thermal burns and tissue damage. Safety measures include maintaining safe distances, using shielding materials like aluminium foil, and limiting exposure time to prevent heat buildup in tissues.

Question 1: Explain why gamma rays are considered the most dangerous form of electromagnetic radiation and include in your answer how their energy compares to that of visible light.

Answer: Gamma rays are the most dangerous because they are ionising and have very high energy, capable of damaging DNA and tissues. Their energy levels are much higher than visible light, which is non-ionising and generally not harmful at typical exposure levels.

Question 1: Describe how safety regulations are implemented in the use of X-ray machines in hospitals to protect patients and staff.

Answer: Regulations include using lead shields, limiting exposure time, maintaining appropriate distance, regular equipment checks, and staff training on radiation safety protocols.

Question 2: Discuss the role of UV protection in everyday life and how it helps prevent health hazards associated with UV radiation.

Answer: UV protection, such as wearing sunscreen, sunglasses, and protective clothing, reduces skin damage and the risk of skin cancer. It helps prevent UV-induced DNA damage in skin cells, especially during prolonged outdoor activities.