Understanding the generation and absorption of electromagnetic waves.
Describing hazards associated with ultraviolet, X-rays, and gamma rays.
Explanation of radio wave production for higher-tier students.
Generation and Absorption of Electromagnetic Waves
Changes in atoms or nuclei occur when electromagnetic waves are generated or absorbed.
Generation
Lithium Example: Heating lithium causes electrons to move to higher energy levels; upon returning, they emit light (an electromagnetic wave).
Gamma Rays: Emitted from the nuclei of radioactive atoms, resulting in a decrease in nuclear energy.
Absorption
Similar atomic changes occur when electromagnetic waves are absorbed, such as electrons changing energy levels.
Electromagnetic waves can be emitted and absorbed across a broad frequency range, from radio waves to gamma rays.
Hazards of Electromagnetic Radiation
Ultraviolet Waves
Increase the risk of skin cancer.
Cause premature skin aging.
X-rays and Gamma Rays
Characterized as ionizing radiation (they knock electrons off atoms when absorbed).
Can cause gene mutations, increasing cancer risk.
Radiation Dose
The damage is dependent on both the type and the dose of radiation.
Dose is measured in sieverts or millisieverts.
Understanding of radiation dose measurements is not typically required for exams, but interpretation of data may be necessary.
Production of Radio Waves (Higher Tier)
Produced by electrons oscillating in an electrical circuit (oscillation = moving back and forth).
Absorbed radio waves can cause electrons in a circuit (e.g., an aerial) to oscillate, generating an alternating current with the same frequency as the radio waves.
Additional Resources
Additional practice questions available in the revision workbook.