Friday, May 13, 2011

3.14

Light waves are transverse waves which can be....
- reflected (eg from a surface of the mirror or body of water)
- refracted (as it passes from air through a different medium, changing its speed)
- diffracted (as it passes through small gaps etc.)


experiment: using laser beam

3.15

3.15) Recall that the angle of incidence equals the angle of reflection.



*All angles are calculated from the normal line.

eye.jpg

Properties of an image in a plane mirror are:
  1. The image and the object are equal distances from the mirror.
  2. The image is laterally inverted. (Which is why an object appears to be back to front in a mirror, left becomes right and right becomes left.)
  3. The image is virtual or imaginary as there is no light actually meeting at that point. You see the image because your brain thinks it is there - your brain always assumes that light has travelled in a straight line!
All waves can be reflected, but need different surfaces to reflect them. For example, high frequency sound waves can be reflected off dense materials in the body, and this is used to see a picture of babies in the womb - for instance, ultrasound.
(Pictures and information taken from... http://www.s-cool.co.uk/category/subjects/a-level/physics/reflection-refraction-and-polarisation) 


Tuesday, May 10, 2011

3.16

FOR PLANE MIRROR, THE IMAGE IS...
- The same size as the object
- The same distance as the object from the mirror
-Virtual (not real)
- Upright
- Laterally Inverted