Chapter 11 - Light and Geometric Optics

Question 1

What is polarisation?

Answer 1

Polarised means only has waves in one plane where both vectors are fixed
An electromagnetic field has two perpendicular vectors (electric field vector and a magnetic induction vector) at any point

Question 2

State the equation for the law of reflection

Answer 2

I = R at N

where I is the angle of incidence, R is the angle of reflection and the normal is the line perpendicular to the surface

Question 3

What is the difference between a real and a virtual image?

Answer 3

A virtual image has no light rays passing through it

a real image has light rays passing through it and can be projected upon a screen.

Question 4

What is the result of light reflected from a plane mirror

Answer 4

Light reflected off a plane mirror is reflected parallel so image is left/right reversed

Question 5

What are the rules for convex and concave mirrors

Answer 5

If i and o are +ve the image is real
If r and f are +ve it is convergent
is M is +ve the image is erect
when M > 1 the image is enlarged

Question 6

What is the equation for magnification?

Answer 6

M = -i/o

Question 7

What is the index of refraction

Answer 7

n = speed of light in a vacuum/speed of light in a medium

*the greatest refraction is the one that is closest to vertical