Section E: Optics Flashcards
(12 cards)
What does Thin Lenses mean?
are lenses where the centre substances are negligible and the total power is equal to the sum of the surface powers
What is a chief ray?
image always lies on it, passes through lens undeviated and passes through OC
when does a chief ray occur
only in thin lenses
how to find magnification
L/L’
How to find image size
h’ = h x L/L’
How to find position of lens
l’ = n / L’
How to find power leaving the lens
L’ =L + F
How to find power entering the lens
L= n/l
What happens if:Mag is negative
Mag is smaller than 1
Mag is larger than 1
- Negative = inverted
- Smaller = image smaller than object
- Bigger = image bigger than object
when asked to describe the nature of the image
Position, orientation & englared or diminshed
How to find image size with distant object?
Either use trig Or h’ =-f’x tan 0
What happens with a distance object?
L and l = 0 and L’ = F
