Diffraction and interference

• Resources Structure
• Key Stage 4
• Physics
• XVI. Electromagnetic waves
• 87. Diffraction and interference

• Exam Specifications
• Key Stage 4
• AQA GCSE Physics (4451)
• VII. Additional materials
• 37. Additional materials
• Additional materials
• AQA GCSE Science A (4461) Physics
• II. Physics 1b - Radiation and the Universe
• 1. What are the uses and hazards of the waves that form the electromagnetic spectrum?
• to evaluate the possible hazards associated with the use of different types of electromagnetic radiation
• to evaluate methods to reduce exposure to different types of electromagnetic radiation.
• Electromagnetic radiation travels as waves and moves energy from one place to another.
• All types of electromagnetic waves travel at the same speed through a vacuum (space).
• The electromagnetic spectrum is continuous but the wavelengths within it can be grouped into types of increasing wavelength and decreasing frequency: gamma rays, X-rays, ultraviolet rays, visible light, infra red rays, microwaves and radio waves.
• Different wavelengths of electromagnetic radiation are reflected absorbed or transmitted differently by different substances and types of surface.
• When radiation is absorbed the energy it carries makes the substance which absorbs it hotter and may create an alternating current with the same frequency as the radiation itself.
• Different wavelengths of electromagnetic radiation have different effects on living cells. Some radiations mostly pass through soft tissue without being absorbed, some produce heat, some may cause cancerous changes and some may kill cells.
• The uses and the hazards associated with the use of each type of radiation in the electromagnetic spectrum.
• Radio waves, microwaves, infra red and visible light can be used for communication.
• Microwaves can pass through the Earth’s atmosphere and are used to send information to and from satellites and within mobile phone networks.
• Infra red and visible light can be used to send signals along optical fibres and so travel in curved paths.
• Communication signals may be analogue (continuously varying) or digital (discrete values only, generally on and off). Digital signals are less prone to interference than analogue and can be easily processed by computers.
• Electromagnetic waves obey the wave formula: wave speed = frequency × wavelength (metre/second, m/s) = (hertz, Hz) × (metre, m)
• AQA GCSE Physics (4451)
• II. Additional materials
• 1. Additional materials
• Additional materials

light, wave, wavelength, measure, reflection, interference, diffraction, slit, diffraction and interference