7K Waves Flashcards
How are sounds generated?
When particles vibrate.
What type of wave is sound?
Longitudinal
What can’t sounds travel through?
Empty space (a vacuum)
In which direction do sound waves travel?
Particles vibrate parallel to the direction of wave travel.
What has to happen for our brains to interpret sounds?
The vibration reaches our ears
What is the energy transfer in a loudspeaker?
Electrical to Kinetic
What does an oscilloscope do?
It shows what sounds look like on a screen.
What would a wave with high frequency sound like?
Many waves occur in a small amount of time.
Name the 3 bones in the ear.
Hammer, Anvil and Stirrup (Ossicles)
What is the function of the outer ear?
To funnel the sound towards the ear canal
What shape is the cochlea?
Spiral shaped.
How to the signals reach the brain?
Signals are passed from the cochlea to the brain through the auditory nerve.
What are the units for volume of sound?
Decibels (dB)
What is the loudness of a jet plane?
110 decibels
Give 3 reasons for hearing loss.
Being exposed to loud noises, head injuries, was, perforating an ear drum.
What is the hearing range of humans?
20 to 20,000 Hz
What minimum distance should you use to measure sound over?
50 meters
What can we use to reduce human timing errors?
Use an electronic timer or data logger and use a large distance.
Why should we repeat an experiment 3 times?
To calculate a mean.
Which substance does sound travel quickest through?
Solids
Describe the arrangement of particles in a gas.
They are spread far apart
Which substance does sound travel slowest through?
Gases
What is a vacuum?
A space with no particles
What is used to remove the air from the bell jar above?
A vacuum pump
How long does it take light to reach the Earth from the Sun?
8 minutes and 20 seconds
What is the incident ray?
The light going towards something (e.g. a mirror)
What travels faster – light or sound?
Light
Suggest how you should draw ray diagrams.
With a ruler and a sharp pencil
What does the hatch line represent in the diagram above?
The mirror
What angle do you draw the normal at?
90 degrees to the surface of the mirror
What is the law of reflection?
The angle of incidence is equal to the angle of reflection
What is specular reflection?
Reflection of light from a flat smooth surface
What is refraction?
Light bending at the surface of a transparent surface.
What happens to the speed of light as it passes into a denser medium?
Decreases
What happens to the speed of light as it passes into a less dense medium?
Increases
True or false: refraction makes swimming pools look deeper than they are.
False- It makes swimming pools look shallower
What is the normal?
A line at right angles to a surface
Why is it harder to pick up an object from the bottom of the pool than you expect?
Refraction makes objects look closer than they are.
How do archer fish catch their prey?
Firing a jet of water at their prey
What feature do archer fish have to help them catch their prey?
It has 2 hard parts to its eye, one for seeing in water and one for seeing in air.
Why is focusing important?
To get a clear image in our eyes or a camera
Give 2 differences between a real image and the object using a pinhole camera.
The image is upside down and smaller than the object.
What is the name of the nerve that transfers information from the retina to the brain?
Optic nerve
What is the coloured part of the eye called?
Iris
What is the function of a lens?
To refract and focus light
What does photosensitive mean?
Sensitive to light
Name 3 places we would find lenses.
Cameras, telescopes, binoculars, microscopes and corrective glasses
What are the 2 types of lenses?
Convex and concave
What does a prism do?
It splits white light into different colours, called dispersion
What are the 7 colours of the spectrum?
Red Orange Yellow Green Blue Indigo Violet
What are the primary colours of light?
Red, green and blue
What are the secondary colours of light?
Cyan, Yellow and Magenta
How do we make white light?
Mix the 3 primary colours of light together
What colour does a red apple reflect?
Red light
What colour will white paper appear in green light?
Green
Why do objects appear black?
If they absorb all colours and reflect none.
