Chapter 5 Mock Flashcards
What are all the electromagnetic waves
Transverse and travel at the same speed In a vacuum
Explain what would happen in refraction in a rectangular glass block if the light entered at 90*
The light would go straight through, no change in direction and would slow down
Explain what would happen in refraction in a rectangular glass block if the light entered at an angle
Slow down
Bends towards normal when entering glass block - more dense and then when it leaves the block it bends away from the normal
List the waves in the electromagnetic spectrum in order
Radio waves Microwaves Infrared Visible light Ultraviolet X rays Gamma rays
What is the electromagnetic spectrum in relation to radio waves to gamma rays (start to finish )
Continuous
Increases in frequency
Decreases in wave length
What frequencies of waves can we see
20 hertz to 20,000 hertz
What may different substances do to electromagnetic waves
Absorb Transmit Refract Reflect Due to variety in wave length
When the potential dangers of electromagnetic waves increases what else does
Increases frequency
How are microwaves harmful in relation to increase in exposure to electromagnetic radiation
Internal hearing of body cells- can cause cancer
How are infrared waves harmful in relation to increase in exposure to electromagnetic radiation
Skin burns
How are ultraviolet rays harmful in relation to increase in exposure to electromagnetic radiation
Damages surface of cells and eyes leading to skin cancer and eye conditions
How are x rays and gamma rays harmful in relation to increase in exposure to electromagnetic radiation
Mutations or damage to cells in the body
Uses of radio waves
Broadcasting
Communications
Satellite transmissions
Uses of microwaves
Cooking
Communications
Satellite transmissions
Uses of visible light
Vision
Photography
Illumination
Uses of ultra violet
Security marking
Fluorescent lamps
Disinfecting water
Detecting forging bank notes
Uses of x rays
Observing internal structure of objects
Air port security
Scanners
Medical
Uses of gamma rays
Sterilising food and medical equipment
Detecting of cancer and its treatment
How can radio waves be produced
Oscillations In electrical circuits
What can changes in atoms and nuclei do
Generate radiations over a wide frequency range
Caused by absorption of a range of radiations
G to kg and kg to g conversions
G to kg- x1000
Kg to g - /1000
Difference between specular and diffuse reflection
smooth surfaces, such as mirrors, reflect all rays in parallel lines (specular reflection)
rough surfaces scatter light rays in different directions (diffuse reflection) - but each ray still reflects at its own angle of incidence
How do colour filters work
By absorbing certain wavelengths (and colour) and transmitting other wavelengths (and colour).
How does the power of a lens relate to its focal length and shape
The bigger the focal length the more powerful it is, the greater the power the greater refraction of light.
What is the power of a lens
It’s ability to bend light
What is the formula for the power of a lens
1 / focal length of lens
What is a converging lens and its effects on rays of light
A converging lens is a convex lens ()
Parallel rays are refracted to a point called the principal focus/focal point)
Converging lenses focus rays of light to produce a real image- opposite side to object being observed.
What is a diverging lens and its effects on rays of light.
A diverging lens is a concave lens )(
They refract the parallel rays of light so they spread apart from one another and make a smaller image for viewer, on a ray diagram you trace them back to form a VIRTUAL image- image formed on same side as object.
Describe a virtual image
Image that cannot be projected onto a screen
Describe a real image
Image that can be projected onto a screen
Uses of diverging/concave lenses
Eyeglasses, contacts, peepholes, binoculars, telescopes and photography.
Uses of a converging lens
A magnifying glass, telescopes, projectors,
What is refraction due to
Difference in velocity of the waves in different substances e.g.- light travels quicker in a less dense medium and changed direction because it travels slower In a dense material
How does the intensity and wavelength distribution depend on temperature
The higher the temperature of an object the shorter the peak wave length of its spectrum
What is a hot object doing
Radiating more infra red radiation in a given time
How can a body stay at a constant temperature
Radiate the same average power that it absorbs
What will happen to a body if the average Power it radiates is less or more than average power it absorbs
If it absorbs more than it gives out it will become hotter
If it absorbs less than it gives out it will become cooler
What is thermal absorption like in shiny surfaces
Poor absorber &Poor emitter of thermal energy
What is thermal absorption like in matt surfaces
Good absorber & good emitter of thermal energy
What is thermal absorption like in light surfaces
Poor absorber and poor emitter of thermal energy
What is thermal absorption like in dark surfaces
Good absorber and good emitter
What is the temperature of the earth effected by
Factors controlling the balance between incoming radiation and radiation emitted
Eg- global warming means that co2 increases the greenhouse effect. More heat is being trapped by the atmosphere, causing the planet to become warmer.
What is convection
Occurs in liquids and gases
Particles with a lot of heat energy move and take place the particles of less heat energy.
Move from Hot to cold to spread heat
What is conduction
Heat energy moves through a substance by conduction. Metals are good conductors or heat but non metals are poor conductors.
Ions are packed together, hot ones have energy and vibrate and pass it onto others and cause them to vibrate- kinetic energy is transferred from hot parts to cold parts by free electrons.
What are non metals
Bad conductors of heat but good insulator- doesn’t let heat pass through it easily.
What is radiation
Unlike convection and conduction it doesn’t require particles but moves as waves- that’s why we feel infrared radiation from the sun.
What are rough or dull surfaces in relation to infrared radiation
Poor at reflecting but good at absorbing
What are shiny surfaces in relation to infrared radiation
Good reflectors
Poor absorber
What would happen if a a blue book was looked at through a red filter
It would appear black, this is because the red filter will only allow red light to pass through. It will absorb all the other colours of light.
What would happen if a blue book was looked at through a blue filter
The object will still appear blue as the reflected blue light can pass through the filter
