Cell biology flash cards
Flash cards on cell structure, organelles, plant and animal cells, bacteria, diffusion, osmosis, active transport, mitosis and microscopy for school biology.
Flash card deck22 cardsIntermediateSchool
Waves and light flash cards
Flash cards on waves and light: transverse and longitudinal waves, wave speed, the electromagnetic spectrum, reflection, refraction, lenses, sound and hearing.
Free to use, edit, print and study. No account needed: your set stays on this device.
The cards, front and back
- 1Front
What does a wave transfer?
BackEnergy (and information) from one place to another, without transferring matter.
- 2Front
Transverse waves
BackThe oscillations are at right angles to the direction the wave travels. Examples: light and all electromagnetic waves, and ripples on water.
- 3Front
Longitudinal waves
BackThe oscillations are parallel to the direction the wave travels, making compressions and rarefactions. Example: sound waves.
- 4Front
Amplitude
BackThe maximum displacement of a point on the wave from its rest position.
- 5Front
Wavelength
BackThe distance from one point on a wave to the same point on the next wave, such as crest to crest. Symbol λ (lambda), measured in metres.
- 6Front
Frequency and period
BackFrequency is the number of waves passing a point each second, in hertz (Hz). The period is the time for one wave: T = 1 ÷ f.
- 7Front
Wave speed equation
BackWave speed = frequency × wavelength (v = fλ).
- 8Front
A wave has a frequency of 50 Hz and a wavelength of 4 m. What is its speed?
Backv = fλ = 50 × 4 = 200 m/s.
- 9Front
List the electromagnetic spectrum in order of increasing frequency.
BackRadio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. Wavelength decreases in the same order.
- 10Front
What do all electromagnetic waves have in common?
BackThey are transverse, can travel through a vacuum, and travel at the same speed in a vacuum: about 300 000 km/s (3 × 10^8 m/s).
- 11Front
Give one use of each electromagnetic wave.
BackRadio: broadcasting. Microwaves: cooking and satellite links. Infrared: remote controls and thermal cameras. Visible: fibre optics and seeing. Ultraviolet: detecting forged banknotes. X-rays: medical imaging. Gamma: sterilising equipment and treating cancer.
- 12Front
Why are ultraviolet, X-rays and gamma rays hazardous?
BackThey carry more energy. Ultraviolet can damage skin cells and eyes, and X-rays and gamma rays are ionising, so they can damage cells and DNA.
- 13Front
What is the law of reflection?
BackThe angle of incidence equals the angle of reflection. Both angles are measured from the normal, a line at right angles to the surface.
- 14Front
What is refraction?
BackThe change in direction of a wave when it passes from one medium to another at an angle, because its speed changes.
- 15Front
Which way does light bend when it enters glass from air?
BackTowards the normal, because it slows down. When it leaves glass into air, it speeds up and bends away from the normal.
- 16Front
What is total internal reflection?
BackWhen light inside a denser medium hits the boundary at an angle greater than the critical angle, all of it reflects back inside. It is used in optical fibres.
- 17Front
Why does a prism split white light into colours?
BackEach colour refracts by a slightly different amount (dispersion), so they spread out into a spectrum: red, orange, yellow, green, blue, indigo, violet.
- 18Front
Convex and concave lenses
BackA convex (converging) lens is thicker in the middle and brings light rays together at a focal point. A concave (diverging) lens is thinner in the middle and spreads light rays out.
- 19Front
Real and virtual images
BackA real image is formed where light rays actually meet and can be shown on a screen. A virtual image only appears to come from a point, like the image in a flat mirror.
- 20Front
Why can sound not travel through space?
BackSound is a vibration of particles, so it needs a medium such as air, water or a solid. Space is almost a vacuum.
- 21Front
What is the range of human hearing, and what is ultrasound?
BackHumans can usually hear about 20 Hz to 20 000 Hz (20 kHz). Ultrasound is sound above 20 kHz, used for scanning unborn babies and detecting flaws in materials.
- 22Front
How does the pitch and loudness of a sound relate to the wave?
BackA higher frequency gives a higher pitch. A larger amplitude gives a louder sound.
How to use this template
This deck covers waves, sound and light for school physics: what waves transfer, transverse and longitudinal waves, amplitude, wavelength, frequency and period, the wave speed equation with an example, the electromagnetic spectrum with uses and dangers, reflection, refraction, total internal reflection, dispersion, lenses, real and virtual images, sound and the range of hearing. It suits GCSE and IGCSE physics or combined science, Year 9 to Year 11 science, high school physics and a refresher for AP or IB physics. Learn the definitions in Learn mode first, then the spectrum and the equation in Test mode, with spaced repetition repeating anything you miss. Print it double-sided for paired quizzing.
Tips
- Make up a memory sentence for the order of the electromagnetic spectrum and practise writing it in both directions.
- Draw a labelled wave showing amplitude and wavelength, as this is a common question.
- In ray diagrams, always draw the normal with a dashed line and measure angles from it, not from the surface.
- Learn the wave equation with units: hertz times metres gives metres per second.
- To explain refraction, say what happens to the speed of the wave first, then the direction.
Make it fit
- Add Snell's law, refractive index calculations or lens ray diagrams for higher-level courses.
- Add seismic waves (P-waves and S-waves) if your course covers earthquakes.
- Make reverse cards with the use on the front and the electromagnetic wave on the back.
- Split the deck into a waves and sound set and a light set.
Updated October 28, 2026