We will use this mind map to produce a study guide for the exam next Tuesday.
If you have long-sightedness you are unable to see objects at a short distance.
Narrow beams of light
Wide stream of light rays, all moving in the same direction
Bouncing off the surface of a substance
The sending of light in many directions by small particles within a substance. Blue light is scattered more than other colours, causing the sky to appear blue.
Describes a substance that allows most light to pass through it. Objects can be seen clearly through transparent substances.
Describes a substance that allows only some light to pass through it. It is possible to make out large shapes through translucent substances, but objects cannot be seen clearly.
In optics, astigmatism is when an optical system has different foci for rays that propagate in two perpendicular planes. If an optical system with astigmatism is used to form an image of a cross, the vertical...
when white light falls on any surface, some colours are reflected while others are absorbed, a red surface aborbs all of the colours except red. only red light is reflected, same ewith green substance abosorbs all of the colours except green. this happens with blue as well a blue subtance absorbs all colours exvept blue.
Red, Green and blue light can be combined to produce white light. these colours can produce all other colours thats why they are called primary colours., the coloured images that you see on tv or comptuer screens are produced by hundreds of narrow red, green and blue., Blue, Green and red can be combined to produce white light.
colours made by mixing primary colours are called secondary colours
This screen, called the retina, is lined with sight receptors called rods and cones
The image formed on the retina is upside down, but the brain sees it the right way up
light-sensitive cells respond to light by sending signals to your brain through the optic nerve
On its way to the lens, the light travels through a hole in the coloured iris called the pupil., The iris is a ring of muscle which controls the amount of light entering the lens.
The light coming from a nearby object needs to be bent more than the light coming from a distant object. The lens in your eye becomes thicker when you look at nearby objects., The shape of the lens is controlled by the ciliary muscles. When you look at distant objects, these muscles are relaxed and the lens is thin. When you look at nearby objects, the ciliary muscles contract. The suspensory ligaments become slack, causing the lens to bulge.
Optical Fibres, The optical fibres are made so that light is unable to emerge from the side of the glass fibres.
Endoscopes, Endoscopes can be also used for laser surgery. Intense laser beams can be directed into the optical fibres.
Inside Optical Fibres, Different type of endoscope includes:, • Gastroscopes, Which are used to examine the stomach and other parts of the digestive system, • Arthroscopes, Which are used to search for problems in joints like shoulders and knees, • Bronchoscopes, Which are used to see inside lungs
Opical fibres, Optical fibres are used to transmit sound and images over ling distance., They are smaller, lighter, more flexible and more effcient than the electrical cables previously used for long-distance., Telephone, radio and TV comminication.
Electrical signals, Electrical signals from a microphone, television camera, computer or fax machine are converted into plues of light and transmitted along an optical fibre.