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Flashcards in Extra Deck (20)
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1
Q

What is monochromatic light?

A
  • Light that has a single frequency
  • A laser light is an example of a monochromatic light
2
Q

What are the conditions for total internal reflection?

A
  • The medium is entering a substance with a lower optical density
  • The critical angle is exceeded
3
Q

What do Optical Fibre do?

A

Optical fibres transmit light by total internal reflection.

4
Q

What are the key features of an optic fibre?

A
  • Core
  • Cladding
  • Protective Coating
5
Q

What are optical fibres used for?

A
  • Internet providers use optical fibres to set up quick and reliable internet connections.
  • They can be used for endoscopy
6
Q

Do optical fibre lose lots of information?

A

No they don’t they are able to transmit huge amounts of information with few information losses

7
Q

What is a thin converging lens?

A
  • A thin converging lens (curved piece of glass) causes parallel rays of light that pass through it to converge (come together).
  • When a beam of light strikes a thin converging lens, the light is refracted twice.
8
Q

What is the image produced by a conveging lens like when the object is more than two focal lengths from the centre of the lens?

A
  • The image is real
  • The image is inverted
  • The image is diminished (smaller than the object)
  • Examples: the eye and cameras
9
Q

What is the focal length?

A

The focal length is the distance from the centre of the lens to the principal focus

10
Q

What is the optical axis?

A
  • The optical axis is an invisible line at 90 degrees to the face of the lens that passes through the lens’ centre.
  • Light travelling along the optical axis passes through the centre of the lens without being deviated.
11
Q

What is the principal focus?

A
  • Light rays that are parallel to the optical axis pass through the lens and converge (come together) at the principal focus.
  • There is one principal focus on each side of the lens as light can pass through the lens in either direction.
12
Q

What is the image produced by a conveging lens like when the object is between one and two focal lengths from the centre of the lens?

A
  • The image is real
  • The image is inverted (upside down)
  • The image is magnified (larger than the object)
  • Examples are the projector and the photocopier
13
Q

What is the image produced by a conveging lens like when the object is two focal lengths from the lens

A
  • The image is the same size as the object
14
Q

What is the image produced by a conveging lens like when the object is between the principal focus and the centre of the lens?

A
  • The image is erect (the right way up)
  • The image is Virtual
  • The image is magnified
  • The image is also on same side of the lens as the object
  • Am example is a magnifying glass
15
Q

What is the dispersion of light?

A
  • Dispersion is the seperation of white light into a spectrum (range) of colours
  • A rainbow is an example of a spectrum that is formed when sunlight is dispersed by raindrops.
16
Q

What are the safety precautions taken while using X-Rays?

A
  • Due to the dangerous nature of X-rays, exposure to X-rays should always be kept to a minimum.
  • People working with X-ray equipment should always shield themselves to prevent exposure to X-rays.
  • These people will place materials (metals for example lead) between themselves and the X-rays.
17
Q

What are the risks of Infra-red radiation

A
  • Infra-red radiation can cause serious skin burns if emitted from high-intensity sources.
18
Q

What are the risks of microwaves (the actual wave)?

A
  • Because humans are largely made up of water, exposure to microwaves could have a harmful effect.
19
Q

What are risks of radio waves?

A
  • At high intensities, radio waves can cause internal heating of living tissue with potentially harmful effects.
20
Q

What are sound waves?

A
  • Sound waves are longitudinal waves.
  • Sound is produced by the vibration of particles in a medium (the substance that waves travel through).
  • The vibrations mean that sound waves travel in a series of compressions (where the medium is squashed together) and rarefactions (where the medium is stretched apart).