Question 1: Define ultraviolet (UV) radiation and explain how it can be dangerous to human skin.

Answer: Ultraviolet (UV) radiation is a type of electromagnetic wave with a wavelength shorter than visible light. It can be dangerous because it can cause skin burns, premature aging, and increase the risk of skin cancer by damaging DNA in skin cells.

Question 2: Describe the mechanism by which gamma rays can damage human tissue at the cellular level.

Answer: Gamma rays are high-energy electromagnetic waves that can penetrate cells and tissues, ionizing molecules and damaging DNA. This ionization can lead to mutations, cell death, and increase the risk of cancer.

Question 3: Calculate the energy (in joules) of a gamma ray photon with a wavelength of 1 x 10^-12 meters. Use the formula E = hc/λ, where h = 6.626 x 10^-34 Js and 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 4: Identify two safety precautions that should be taken when working with X-ray equipment in medical or industrial settings.

Answer: Wearing lead aprons and shields to protect against radiation exposure; limiting exposure time and maintaining a safe distance from the source.

Question 5: Explain why radio waves are considered safe for human exposure despite their widespread use in communication devices.

Answer: Radio waves have very low energy and do not ionize molecules, so they do not cause damage to human tissues. They are non-ionizing radiation, making them safe at typical exposure levels.

Question 6: Multiple Choice: Which type of electromagnetic wave poses the highest risk of causing cancer due to DNA damage?

Answer: Ultraviolet radiation

Question 7: Fill in the blank: The primary danger of microwave radiation in domestic microwave ovens is due to absorption by water molecules, which causes them to vibrate and generate ________.

Answer: heat

Question 8: Describe how ultraviolet (UV) radiation can cause sunburn and what protective measures can be taken to reduce the risk.

Answer: UV radiation causes sunburn by damaging the outer skin layers and DNA within skin cells, leading to inflammation and redness. To reduce risk, individuals should wear sunscreen with high SPF, wear protective clothing, and avoid prolonged exposure during peak sunlight hours.

Question 9: Data Analysis: A study reports that exposure to X-ray radiation at a medical dose of 0.1 Gy increases the risk of DNA mutations by 20%. If a person is exposed to 0.5 Gy in a session, what is the estimated increase in mutation risk? Assume the risk increases linearly with dose.

Answer: Increase in risk = (0.5 Gy / 0.1 Gy) x 20% = 5 x 20% = 100%

Question 10: Identify a technological application where understanding the dangers of electromagnetic waves is critical for safety, and explain the safety measures implemented.

Answer: In MRI (Magnetic Resonance Imaging), understanding the risks of radiofrequency radiation is essential. Safety measures include limiting exposure time, using shielding, and ensuring patients and staff wear appropriate protective gear.