Light and Sound Flashcards
How is sound made?
Sound is produced whenever an object vibrates.
How does sound travel?
Sound transfers energy away from the vibrating object, and it needs something (matter) to travel through. Sound cannot travel through a vacuum (outer space). Sound travels faster through solids because the particles are closer together, so the vibrations are more efficiently passed from particle to particle.
Define “Amplitude”
The height of a crest (top) or trough (bottom) of a wave when measured from the rest position.
Define “Frequency”
The number of waves that pass a point in one second. Measured in Hertz (Hz)
Define “Wavelength”
The maximum distance between two crests or troughs.
Explain why you can hear sound across a much greater distance underwater than you can when in air.
Because sound travels faster and for longer in liquids than gases (the air), as the particles are closer together so the vibrations are more efficiently passed from one particle to particle.
Explain why you can see the light from the sun but you cannot hear the massive explosions that are occurring on the sun.
Because light travels faster than sound, and sound needs something (matter) to travel through, sound cannot travel through a vacuum (no matter) such as outer space.
Define “Pitch”
Pitch is a term used to describe the frequency of a sound wave. A larger frequency equates to a higher pitch.
Define “Loudness”
Loudness is related to amplitude. A larger amplitude means a louder sound.
Write down the missing words in these sentences. ‘When something makes a noise, it sends ____________ or sound waves through the air. The outer ear, or _______ focuses the sound into your ____________ ___________. The sound travels down the canal until it reaches your ___________. The eardrum is a stretched membrane, like the skin of a _______. When the sound waves hit you eardrum, it ____________. Your eardrum, which is smaller and thinner than the nail on your little finger, sends the vibrations to the three smallest _______ in your body. First the __________, then the anvil, and finally, the __________. The stirrup passes those vibrations along a coiled tube in the inner ear called the ____________. Inside the cochlea there are thousands of hair-like nerve endings, called cilia. When the cochlea vibrates, the cilia _______. Your brain is sent these messages as electrical signals (translated from vibrations in the cilia) through the ____________ nerve. Your brain then translates these signals and interprets them as sounds. Loud noises ________ the cilia inside the cochlea causing them to break. This means they can no longer sense the vibrations caused by __________ waves, resulting in __________ loss.
Vibrations, pinna, auditory canal, eardrum, drum, vibrates, bones, hammer, stirrup, cochlea, move, auditory, damage, sound, hearing.
What is a wave?
Waves are vibrations that transfer energy as they move. Both sound and light travel as waves. There are two different types of waves - transverse waves and longitudinal waves.
What is light?
Light is a form of energy called electromagnetic radiation. It occurs as waves and includes visible light, invisible light (such as infrared and ultraviolet), x-rays, microwaves and radio waves.
How does light travel?
Light travels in straight lines, and can travel through a vacuum. The speed of light is quicker than the speed of sound.
Light is an active form of _______ that is produced by light sources. ________ objects are classified as __________. Light _________ from a light source which means it travels outwards in all directions as _______. Light rays travel in ________ lines at 300,000 ________. When a light ray strikes an object it can either be __________ off the __________ of the object or it can pass into the object. Light can pass through the object unaffected (be ________) or it can be _________. If all light passes through the object, the object is ____________, if some (but not all) light passes through the object is ___________. If the object absorbs all light, it is _________.
Energy, sources, reflectors, radiates, waves, straight, km/sec, reflected, surface, transmitted, absorbed, transparent, translucent, opaque.
Give some examples of transparent objects.
air, water, clear glass.
Give some examples of translucent objects.
thin sheets of plastic, fingers, sunglasses.
Give some examples of opaque objects.
cardboard, book, wood.
What is a light source? Give some examples.
A light source is something that creates/produces its own light. e.g: the sun, a lightbulb, a match.
What is a reflector? Give some examples.
A reflector is anything that reflects something. It does not create its own light. e.g: shirt, desk, arm.
Label this diagram
What type of reflection is this?
regular (specular)
What type of reflection is this?
Diffuse.
Name these mirrors.
Convex Mirror on the left, and Concave Mirror on the right.
Reflection off a concave mirror, where do points A,B,C go?
A goes to point F, B goes to point E, C goes to point D.
Reflection off a convex mirror, where do points A,B,C go?
A goes to D, B goes to E, C goes to F.
Fill in the gaps about a concave mirror
Inwards, Converge, A Focal.
Fill in the gaps about a convex mirror.
Outwards, Diverge, No Focal.
Fill in the gaps about refraction.
Transmitted, transparent, medium, water, solid, direction, refraction, broken, magnified, position.
Fill in the gaps.
The light ray in this diagram is moving from a ______ dense medium (air) to a _____ dense medium (water). This causes the light ray to ______ _______ at the interface. This, in turn, causes the light ray to bend _______ the normal so that angle i is _______ than angle r.
Less, more, slow down, towards, larger.
Names these converging lenses in order.
Convex lens, biconvex lens, plano-convex lens, positive meniscus.
Name these diverging lenses in order.
Concave lens, bi-concave lens, plano-concave lens, negative meniscus.
Fill in the gaps about a concave lens.
Concave lenses are often referred to as _______ lenses because parallel rays of light move ______ when they pass through the lens.
Diverging, apart.
Fill in the gaps about convex lenses.
Convex lenses are often referred to as _________ lenses because, when parallel rays of light pass through the lens, they come __________ and cross at a ________ point.
Converging, together, focal.
