Topic 4 Flashcards
How do waves transfer energy
Waves transfer energy without transferring matter
The waves move but not the particles
Wavelength
Distance between the same points on two consecutive waves
Amplitude
The height of waves from the line
Waves with more energy- higher amplitude
Frequency
Number of waves which pass a single point per second
Period
The time taken for a wave to completely pass a single point
Wave front
The direction of the wave
What does v = f × lamda mean
Wave Speed = frequency x wave length
What happens if you increase velocity
Increases frequency
What happens if you make the period smaller
Higher frequency
Greater velocity
Examples of transverse waves
Light , seismic waves , water
Examples of longitudinal waves
Sound waves , seismic p waves
Ehat is a transverse wave
A wave where the vibrations are at right angles , perpendicular, to the direction of wave travel
I. I. I
I. I. I. I. I
I. I. I. I. I
I. I. I
What is a longitudinal wave
wave that moves in the same direction as the direction in which the particles are vibrating
IIIL. IIII. III
II. IIIII. IIII
How to measure speed of sound in air
- Stand 50 m from wall and make noise
- Have to microphones connected to a data logger and record the time it takes to pass from one to other
3.use speed = distance ÷ time
What is refraction
When waves pass from a medium to a denser medium (air and glass)
It causes the wave to refract
What happens when a wave refracts?
The wave will refract at the boundary and will change direction to go towards the normal
Speed decreases
Wavelength decrease
What is reflection
Waves only reflect off flat surfaces
Features of reflection
The smoother the surface the better the reflection
Rough surfaces may scatter the light
Angle of incidence = angle of relections
Electrons absorb light energy and emmit it as a reflected wave
What happens when you hear a noise?
- Outer ear collects sound an channels it down ear canal
- The sound waves hit eardrum
- Eardrum vibrates at same frequency as sound wave
- The small bones vibrate at same frequency
What happens after you hear a noise ?
After small bones vibrate at same frequency as eardrum
- Vibrations of small bones transferred to fluid in the inner ear called the cochlea
- Small bones act as an amplifier
3.as the fluid moves due to compression waves the small hairs in the cochlea move too
4.each hair can detect a specific frequency - When that frequency is detected it sends signals to the brain
How to scan for fetuses
An infrasound wave creates an image of the foetus because they partially reflect at each surface
Uses of electromagnetic spectrum
Radio- communication,
Microwave- cooking
IR - thermal imaging
Uv - security marking
X rays- pbserveing internal structure of objects
Gamma - sterilising food equipment
