P12 Flashcards
What type of lens is thicker in the middle than at the edges?
Convex lenses
Which type of lens causes light rays to diverge?
Concave
Which type of lens is used in a camera?
convex
What is a real image?
A real image is an image that can be projected onto a screen
What is a virtual image?
An image from which rays of light appear to come but do not do so in reality
What types of images do concave lenses form?
Only virtual images
What name is given to a material that absorbs some wavelengths of visible light and transmits others?
A filter
Why can we see through glass?
Almost all light waves are transmitted through glass, making it a transparent object
What name is given to the distance between the lens and the principal focus?
Focal length
What is an area of low pressure in a wave called?
A rarefraction
What is denser (air, glass or water)?
Glass
What happens to a light ray when it travels from water into air?
It bends away from the normal because it passes into a less dense material and speeds up
What are the units for magnification?
Magnification has no units since it is a ratio of 2 quantities with the same units.
What state of matter does sound travel the fastest?
Solids, because the particles are more tightly packed
Waves transfer ____
energy from place to place, without transferring any matter
What is the amplitude?
The amplitude of a wave is the distance from the centre line (or the still position) to the top of a crest. or to the bottom of a trough.
What is frequency?
Frequency is the number of complete waves passing a certain point per second measured in Hz. 1 Hz is equal to 1 wave per second.
What is wavelength?
The wavelength of a wave is the distance between a point on one wave and the same point on the next wave.
What are transverse waves?
Transverse waves are waves whose oscillations are at right angles to the direction of travel and energy transfer.