Physics - Light (Refraction)

why does light slow down/bend when it moves from one medium to another?

When light crosses the boundary between two different mediums, its electric field interacts with the electric fields of the atoms in the new medium.

This interaction creates a counterbalanced field, which alters the light’s own electric field, changing the properties of light.

As a result, the direction of the light wave changes — a process known as refraction.

What happens when waves meet each other?

• it is called superposition

• the 2 ways it can happen are:

• Constructive interference - when 2 waves add together to make a bigger wave

• Destructive Interference - when 2 waves cancel each other out or make a smaller wave

What is Snell’s law?

Snells’ law is a formula used to determine the relationship between the angle of incidence and refraction, when light passes through a boundary from one media to another

What happens to light when it hits a surface which it can transmit through?

The light gets refracted, and the directions of it changes

The light bends when it moves from one medium to another

What does an electromagnetic wave consist of?

consists of 2 oscillating field, 1 electric and 1 magnetic which moves in a vacuum carrying energy

What does the properties of light depend on?

Properties of light such as speed and direction are based on its 2 oscillating fields

What happens when light enters another medium?

Light’s electric field imposes on the new medium’s electric field

This interaction causes the +’s and -’s to move around and create a counter balanced electric field

This counterbalanced electric field causes change in light’s electric field, which then leads to change in the direction of motion of the light wave

What happens when the medium slows light down?

light bends towards the normal

What happens when the medium speeds light up?

light bends away from the normal

What’s the refraction when angle of incidence is 0 degrees and 60 degrees?

0 = no refraction

60 = no refraction, lots of reflection

What happens as the angle of incidence increases?

the angle of refraction increases until it refracts along the boundary of the 2 mediums

What happens when the angle is greater than the critical angle?

total internal reflection takes place

this means that no light refracts anymore

When does total internal reflection occur?

1. light moves from a more optical dense medium to a less optical dense medium

2. The angle of incidence is greater than the critical angle

What do you use to calculate the critical angle?

Snell’s law

What is the interaction between 2 waves called?

superposition

What is a resultant wave?

Light’s electric wave imposes another wave, it created a new wave called the resultant wave, with the materials it moves through

What is a lens?

a transparent glass or plastic with at least 1 curved surface that can focus light to create an image

How are lenses different from mirrors?

Instead of reflecting light, they refract it

In a lens, how many times is light refracted and where?

2 times

Once when it enters and again when it leaves the lens