Extra Flashcards Preview

Physics > Extra > Flashcards

Flashcards in Extra Deck (20)
Loading flashcards...
1

What is monochromatic light?

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

2

What are the conditions for total internal reflection?

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

3

What do Optical Fibre do?

Optical fibres transmit light by total internal reflection.

4

What are the key features of an optic fibre?

  • Core 
  • Cladding 
  • Protective Coating 

5

What are optical fibres used for?

  • Internet providers use optical fibres to set up quick and reliable internet connections.

  • They can be used for endoscopy

6

Do optical fibre lose lots of information?

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

7

What is a thin converging lens?

  • 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

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?

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

9

What is the focal length?

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

10

What is the optical axis?

  • 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

What is the principal focus?

  • 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

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?

  • 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

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

  • The image is the same size as the object 

14

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

  • 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

What is the dispersion of light?

  • 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

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

  • 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

What are the risks of Infra-red radiation 

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

18

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

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

19

What are risks of radio waves?

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

20

What are sound waves?

  • 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).