diffraction and interference

Question 1

what are convex lenses?

Answer 1

they are positive converging lenses

image formed can be real or virtual or no image formation

Question 2

what are concave lenses?

Answer 2

they are negative diverging lenses

image formed is always virtual

Question 3

what is a convex mirror?

Answer 3

negative mirror

image formed is always virtual

Question 4

what is a concave mirror?

Answer 4

positive mirror

image formed can be real or virtual or no image formation

Question 5

what is the similarity between lenses and mirrors?

Answer 5

.if object height and image height are above optical axis they are positive
. if object height and image height are below optical axis they are negative

Question 6

what is the difference between lenses and mirrors?

Answer 6

lenses - if object or image distance is measured from left then its negative
mirror- if object or image distance is measured from right then its positive

Question 7

what is interference?

Answer 7

1. monochromatic light is split into two paths by a beam splitter
2. half amount of light going in each path
3. mirrors are used to bring two paths together
4. the amount of light reaching screen is observed

Question 8

explain anti - reflection coating?

Answer 8

. some of light is transmitted through surface of glass
. 2 rays coming back
. reflection cancels out at retina

Question 9

what is constructive interference?

Answer 9

.if two waves meet peak on peak you get constructive interference
. double amplitude

Question 10

what is destructive inttererence?

Answer 10

. if two waves meet peak and trough

. 2 lights cancel out so no light

Question 11

what is diffraction?

Answer 11

. diffraction is the fact that waves spread out as they go through a narrow gap or round obstacles

Question 12

what does diffraction depend on?

Answer 12

amount of diffraction depends on wavelength of wave compared to size of gap
large aperture = small diffraction
small aperture = bigger diffraction