Waves Flashcards
What is a transverse wave?
A wave in which the medium vibrates at right angles to the direction of the wave.
What is a longitudinal wave?
A wave in which the medium vibrates back and forth in the same direction as the wave.
What are examples of a transverse wave?
Electromagnetic waves (light waves), water waves, guitar string vibrations
What are examples of longitudinal waves?
Sound waves, slinkies, earthquakes
What is the speed of sound in air?
340m/s
What is the speed of light in air?
3 x 10(8) m/s
What is wavelength?
The distance between two adjacent identical parts of a wave (i.e. two peaks or two troughs)
What is the formula for distance, speed and time?
d (distance) units: m (metres)
v (speed/velocity) units: m/s (metres per second)
t (time) units: s (seconds)
What is a period?
The amount of time it takes for one cycle (wavelength) to pass by.
What is frequency?
How many wavelengths pass by in one second.
What is the formula for frequency, the number of waves, and time they take to pass?
f=N/t
What is the formula for speed, frequency and wavelength?
v (units: m/s)
f (units: Hz (hertz))
lambda (units: m (metres))
What is the range of human hearing?
20Hz - 20,000Hz
What is sound below 20Hz called?
Infrasound
What is sound above 20,000Hz called?
Ultrasound
What does sound do when it meets a change in medium?
It reflects
What is the speed of sound in water?
1500m/s
What are the seven types of waves on the electromagnetic spectrum, from longest to shortest wavelength?
Radio waves, microwaves, infrared, visible light, ultraviolet (UV), X-rays and gamma rays
What is diffraction?
The bending of waves around an object.
Do longer or shorter wavelengths diffract more?
Longer wavelengths. Shorter wavelengths reflect more and bounce off of the change in medium.
What is a use for radio waves?
Carrying radio and TV programmes. The long wavelength allows the waves to diffract around building and hills, thus reaching more receivers.
What is a use for microwaves?
Cooking food and satellite communication
What is a use for infrared waves?
Infrared waves is another word for heat. It can be used in thermograms and healing damaged tissue
What is a use for visible light?
Lasers as scalpels, laser eye surgery
What is a use for ultraviolet light?
Treating skin (acne), security markings on bank notes (can also cause cancer)
What is a use for X-rays?
Creating images of bones inside the body
What is a use for gamma rays?
Killing cancer cells, killing bacteria, tracers
