Module 3 Part 4 : Ray Model of Light

Question 1

what is the law of reflection

Answer 1

angle of incidence(i) = angle of reflection(r)

Question 2

why does light bend when it goes through a medium

Answer 2

refraction

Question 3

what is refraction

Answer 3

the bending of light as it moves between media of different densities

Question 4

how does density effect the direction of light

Answer 4

it changes the lights speed, which causes the light to change direction

Question 5

what happens when a light ray moves through a more dense medium

Answer 5

bends away from the normal

Question 6

what happens when a light ray moves through a less dense medium

Answer 6

bends towards the normal

Question 7

what happens when the light enters along the normal

Answer 7

the light will not refract

Question 8

what is the normal

Answer 8

the normal is a line that is 90 degrees to a surface

Question 9

what is Snell’s law (2)

Answer 9

As light enters a more dense medium the wavelength and velocity decrease
Frequency remains the same (colour is the same)

Question 10

what is the equation of Snell’s law

Answer 10

n₁ sinθ₁ = n₂ sinθ₂

Question 11

what is the symbol for refractive index

Answer 11

n

Question 12

what is θ₁ in Snell’s law

Answer 12

the angle of incidence

Question 13

what is θ₂ in Snell’s law

Answer 13

the angle of refraction

Question 14

what is the equation to find the refractive index

Answer 14

n = c/vₙ

Question 15

what is c in the refractive index equation

Answer 15

speed of light

Question 16

what is vₙ in the refractive index equation

Answer 16

speed of light in the medium

Question 17

what unit is refractive index measured in

Answer 17

it has no unit

Question 18

how is total internal reflection achieved

Answer 18

when the light ray angle of incidence is above the critical angle of the light

Question 19

what is the critical angle

Answer 19

the angle of incidence that provides an angle of refraction of 90-degrees.

Question 20

what is the symbol for critical angle

Answer 20

θ𝒸

Question 21

what is the critical angle formula

Answer 21

sinθ𝒸 = n₂/n₁

Question 22

what type of lenses are there (2)

Answer 22

concave

convex

Question 23

what happens when beams of light go through a convex lens

Answer 23

all beams go through the focal point

Question 24

what happens when beams of light go through a concave lens

Answer 24

they bend out so that there origin is the focal point

Question 25

what are the rules when locating an image formed by a convex lens (3)

Answer 25

A ray parallel with the optical axis passes through the focus
A ray that passes through the centre of the lens does not bend
A ray which passes through the focus will bend to be parallel

Question 26

how are images characterised (3)

Answer 26

real or fake
inverted or not inverted
reduced or enlarged

Question 27

what are the rules for finding an image in a mirror

Answer 27

A ray parallel to the principal axis will reflect through the focus
A ray passing through the centre of curvature of the mirror will reflect back along itself
A ray striking the centre of the mirror will reflect to make a symmetrical line in a “V” shape
A ray passing through the focus is reflected parallel to the principal axis

Question 28

what are the equations of the inverse square law

Answer 28

I₁r₁² = I₂r₂²