Flashcards
2. Waves
Flashcards do conjunto (95)
- 1What do waves transfer?Energy and information without transferring matter
- 2What are the oscillations in a transverse wave like?Perpendicular to the direction of energy transfer
- 3What are the oscillations in a longitudinal wave like?Parallel to the direction of energy transfer
- 4What do longitudinal waves show?Areas of compression of rarefaction
- 5What type of waves are electromagnetic waves?Transverse
- 6What type of waves are sound waves?Longitudinal
- 7What type of waves are mechanical waves?Either
- 8What can be done to waves?They can be reflected, refracted and diffracted
- 9What happens when identical sets of waves overlap?They interfere with each other
- 10How can waves be described?In terms of their frequency, wavelength, time period and amplitude
- 11What is the frequency of a wave?How frequent the waves are
- 12What is the wavelength of a wave?The length from peak to peak, or trough to trough
- 13What do all electromagnetic waves do?Trave; at the same speed through a vacuum (space)
- 14What is the order of the electromagnetic spectrum?Radio waves
Micro waves
Infrared
Visible light
Ultra-violet
X-ray
Gamma - 15What are the properties of the different ends of the electromagnetic spectrum?
- 16Which waves are used for communication?Radio waves, microwaves and visible light
- 17What is a use for radio waves?Television, radio and bluetooth
- 18What is a use for microwaves?Mobile phones and satellite tv
- 19What is a use for infrared?Remote controls
- 20What is a use of visible light?Photography
- 21What is a use of ultraviolet?Security marking
- 22What is a use of x-rays?Medical imaging
- 23What is a use of gamma rays?Sterilising surgical instruments and killing harmful bacteria in food
- 24What is a hazard of microwaves?Heating of body tissue
- 25What is a hazard of infrared?Skin burns
- 26What is a hazard of ultraviolet?Skin cancer and blindness
- 27What is a hazard of x-ray?High doses can kill cells
- 28What is a hazard of gamma rays?Genetic mutations
- 29What do x-rays cause?Ionisation
- 30What are properties of x-rays?They affect a photographic film in the same way as light
They are absorbed by metal and bone
They are transmitted by soft tissue - 31What are the medical uses of x-rays?Used to diagnose medical conditions (computed tomography) e.g. Scanning, bone fractures and dental problems
They are also used to treat conditions e.g. killing cancer cells - 32What can the use of high energy ionising radiation be?Dangerous, and precautions need to be taken to monitor and minimise the levels of radiation that people who work with it are exposed to
- 33What do sound waves do?They cause vibrations in a medium, which are detected as sound
- 34What is the range of human hearing?20 Hz - 20,000 Hz
- 35What is the pitch of a sound determined by?The frequency
- 36What is the loudness of a sound determined by?The amplitude
- 37What can be done to sound waves?They can be reflected (echoes) and diffracted
- 38What is ultra-sound?Acoustic sound energy with a frequency above the human hearing range
- 39What are electronic systems used for?To produce ultrasound waves
- 40How can you use ultrasound to determine how far away a boundary is?Ultrasound waves are partially reflected when they meet a boundary between two different media
The time taken for the reflections to reach a detector - 41What are ultrasound waves used for in medicine?Pre-natal scanning and the removal of kidney stones
- 42What is the normal?A construction line perpendicular to the reflecting surface at the point of incidence
- 43How do you describe the image produced by a plane mirror?Virtual and flipped along the horizontal axis
- 44What happens when light enters a more dense medium?It is refracted towards the normal
- 45What happens when light enters a less dense medium?It is reacted away from the medium
- 46What happens when waves are traveling along the normal?They are not refracted
- 47Why are waves refracted?Due to a change of speed
- 48What leads to dispersion?Refraction by a prism
- 49What is the refractive index of a medium defined as?Speed of light in vacuum (air)
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Speed of light in the medium - 50When does total internal reflection occur?If the angle of incidence within the more dense medium is greater than the critical angle
- 51What do optical fibres do?Transmit visible light by total internal reflection
e.g. The endoscope for internal imaging - 52How does a lens form an image?By refracting light
Each section of a lens acts like a tiny prism
Each section refracting light as it goes in and again as it comes out - 53What happens in a convex lens?Parallel rays of light are brought to a focus at the principal focus
- 54What is another name for a convex lens?A converging lens
- 55What are converging lenses used for?Magnifying glass, Projector, in an eye or a camera
- 56What does the amount of magnification of a convex lens depend on?How curved the surface of the lens is
How close the lenses are placed - 57What does a diagram for a converging lens look like?
- 58What type of image does a magnifying glass produce?Virtual, upright and magnified image
- 59What does a magnifying glass lens diagram look like?
- 60What type of image does an eye or camera produce?Real, inverted and diminished image
- 61What does an eye or camera lens diagram look like?
- 62What type of image does a projector form?A real, inverted and magnified image
- 63What does a projector lens diagram look like
- 64What is the focal length?The distance from the lens to the principle focus
- 65What is the focal length depend on?The reactive index of the material from which the lens is made
The curvature of the two surfaces of the lens - 66For a given focal length, what happens to the refractive index if the lens is flatter?The refractive index is greater
This means that the lens can be manufactured thinner - 67What happens in a concave lens?Parallel rays of light diverge as if coming from the principle focus
- 68What is another name for a concave lens?A diverging lens
- 69What type of image does a diverging lens produce?Virtual, upright and diminished liquid
- 70What does a diverging lens diagram look like?
- 71What unit is the power of the lens measured in?Dioptre or m-1
- 72What does the retina do?The retina contains light receptors and lines the back of the eye
- 73What does the lens do?It is bi-convex and flexible disc and it focuses light onto the retina
- 74What does the cornea do?It is convex and transparent and it refracts light - bend it as it enters the eye
- 75What does the pupil do?The pupil is where the light gets into the eye
- 76What does the iris do?It contracts and relaxes to change the size of the pupil and control how much light enters the pupil
It is also pigmented - 77What does the ciliary muscle do?It is a circular muscle that relaxes or tightens to enable the lens to change shape for focusing
- 78What do the suspensory ligaments do?Slacken or stretch as the ciliary muscles contract or relax, to adjust the thickness and curvature of the lens
- 79What is the usual near point of the human eye?25cm
- 80What is the usual far point of the human eye?Infinity
- 81What objects can the eye focus on?Objects between the far point and the near point
- 82What is the distance between the near and far point called?The range of vision
- 83What is long sightedness caused by?The eyeball being too short or the eye lens being unable to focus
- 84What is short sightedness caused by?The eyeball being too long or the eye lens being unable to focus
- 85What type of lens corrects short-sightedness?Concave
- 86What type of lens corrects long-sightedness?Convex
- 87What can be used to correct visual defects other than glasses?Lasers (concentrated source of light which can be used for cutting cauterising and burning) can be used in eye surgery
- 88What will happen if a wave source is moving relative to an observer?There will be a change in the observed wavelength and frequency
This is called the Doppler effect - 89What could the wave source in the Doppler effect be?Light, sound or microwaves
- 90What happens when the wave source is moving away from the observer?The observed wavelength increases
The observed frequency decreases - 91What happens when the wave source is moving towards the observer?The observed wavelength decreases
The observed frequency in decreases - 92What is red-shift?When there is an observed increase in the wavelength of light from most distant galaxies
The further away the galaxy, the larger the wavelength increase - 93What does red-shift provide evidence for?The big bang theory
If galaxies are moving away from each other the universe must have bagan from an initial point - 94What is cosmic microwave background radiation (CMBR)?A form of electromagnetic radiation filling the universe
- 95Where does CMBR come from?From radiation that was present shortly after the beginning of the universe
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- GCSE Physics FlashCards sobre 2. Waves, criado por Grace Isaac em 14-05-2016.
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- Grace Isaac
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