P6-Waves Flashcards
What do waves do?
Waves transfer energy from one place to another without transferring any matter.
What direction do waves transfer energy?
The direction they are travelling.
Describe particles and energy in a wave?
Overall, the particles stay in the same place - only energy is transferred.
What is amplitude?
Amplitude of a wave is the maximum displacement of a point on the wave from its undisturbed position.
What is wavelength?
Distance between the same point on two adjacent waves. (E.g the trough of one wave to the trough of the next wave).
What is frequency?
The number of complete waves passing a certain point per second. Frequency is measured in hertz. 1Hz = 1s
What is the period of a wave?
Amount of time it takes for a full cycle of the wave.
All waves are either….
Transverse or longitudinal.
Describe transverse waves vibrations?
They have sideways vibrations.
Describe longitudinal waves vibrations?
Have parallel vibrations.
What is wave speed? What is the equation?
The speed at which energy is being transferred (or speed the wave is moving at).
Wave speed = Frequency x wavelength.
When a wave meets a boundary what 3 thing might happen?
The wave is absorbed.
The wave is transmitted.
The wave is reflected.
What happens when a wave is absorbed?
The wave transfers energy to the material’s energy stores. Often, the energy is transferred to a thermal energy store, leading to heating.
What happens when a wave is transmitted?
The wave carries on travelling through the new material. This often leads to refraction. Used in communications and lenses of glasses and cameras.
What happens when the wave is reflected?
The wave is ‘sent back’ away from the second material. This is how echoes are created.
What type of waves are electromagnetic waves? What do they do?
Transverse. They transfer energy from a source to an absorber.
How do EM waves travel?
At the same speed through air or a vacuum (space). EM waves are not vibrations of particles, they’re vibrations of electric and magnetic fields.
Name all waves in order of the spectrum?
1)Radio waves. 2) Micro waves. 3)Infrared. 4)Visible light. 5) Ultra violet. 6) X-rays. 7) Gamma rays.
What is the spectrum baed off of?
Their wavelength and frequency.
What is refraction?
When waves change direction at a boundary.
What happens to the when a wave crosses a boundary?
When it crosses a boundary between two materials it changes speed.
What happens when a wave is travelling along the normal?
It will change speed, but it’s Not refracted
What happens to wavelength and frequency when a wave is refracted?
The wavelength changes. But the frequency stays the same.
Radio waves are made by what type of charges?
Oscillating charges.
What are EM waves made up of?
Oscillating electric and magnetic fields.
What are radio waves mainly used for?
Communication.
What are advantages of long- wave radio wavelengths?
Can be transmitted along large distances. This is because they can diffract (bend) around curved surfaces. They can also diffract around hills, into tunnels etc.
What are microwaves used by?
Satellites.
Why are microwaves used by satellites?
Because they can pass easily through the earth’s watery atmosphere.
Difference between microwave ovens and satellites?
Microwave ovens use a different wavelength.
What can infrared radiation be used for?
To increase or monitor temperature.
Uses of infrared radiation?
Infrared cameras show different objects thermal energy stores.
Through cooking as well.
What are X-rays and gamma rays used in?
Medicine.
Uses of ultraviolet radiation?
Can give a suntan- however high exposure can be dangerous.
When absorbed visible light is emitted.
Security pens.
Also produced by the sun.
What types of waves can cause damage?
High frequency waves such as UV, X-rays and gamma rays because they transfer lots of energy.
Disadvantages of UV radiation?
Damages surface cells, which can lead to sunburn and skin to age. Some more higher risks such as blindness or skin cancer.
