Light and the EM spectrum Flashcards
(56 cards)
What is the definition of refraction?
Refraction is the change in direction of a wave at the boundary between two transparent materials.
Refraction occurs due to differences in density between materials.
What is necessary to illustrate the refraction of a light ray?
It is important to be able to draw ray diagrams to show the refraction of a light ray at a boundary.
Ray diagrams help visualize the behavior of light as it passes from one medium to another.
What can refraction cause in terms of perception?
Refraction can cause optical illusions as the light waves appear to come from a different position to their actual source.
This phenomenon is commonly observed in scenarios such as seeing a straw in water appearing bent.
In a ray diagram, what are the components involved in refraction?
The components involved in refraction in a ray diagram are:
* Incident ray
* Normal
* Refracted ray
The incident ray is the incoming light, the normal is an imaginary line perpendicular to the boundary, and the refracted ray is the light that has changed direction.
Fill in the blank: Refraction occurs at the boundary between two _______ materials.
[transparent]
Transparent materials allow light to pass through, enabling the phenomenon of refraction.
What angles are shown in the ray diagram between air and glass?
The angles shown are 55° for air and 33° for glass.
These angles indicate the direction change of the light as it passes from air to glass.
What happens to a light ray when it passes from air into glass?
It slows down and bends towards the normal.
What is the effect of density on light rays when transitioning from air to glass?
Glass is denser than air, causing the light ray to slow down.
What occurs when a light ray meets the boundary at an angle to the normal?
It bends towards the normal.
What happens to a light ray when it moves from glass into air?
It speeds up and bends away from the normal.
True or False: A light ray bends towards the normal when entering a less dense medium.
False.
Fill in the blank: A light ray _______ as it passes from glass into air.
speeds up.
What is the term for the angle at which a light ray meets the boundary between two mediums?
Angle to the normal.
When a ray of light passes from a denser medium to a less dense medium, it bends _______.
away from the normal.
What occurs when a light ray reaches the boundary between two transparent materials?
It may be refracted or reflected
What happens to a light ray when it leaves a more dense medium?
It is expected to bend away from the normal
What occurs if the refraction would bring the ray out at more than 90° from the normal?
The refraction is not possible and the ray is reflected inside the more dense medium
What is the term used when a ray is reflected inside a more dense medium instead of refracted?
Total internal reflection (TIR)
What is the critical angle?
The angle of incidence when the ray changes from just refracting to total internal reflection
True or False: Total internal reflection occurs when light travels from a less dense to a more dense medium.
False
Fill in the blank: The angle of incidence when a ray changes to total internal reflection is called the _______.
critical angle
What phenomenon allows light to be contained and guided along very thin fibres?
Total internal reflection
Total internal reflection (TIR) is a key principle used in optical fibres.
What are optical fibres usually made of?
Glass
Optical fibres are typically constructed from glass due to its properties that facilitate total internal reflection.
What is one use of fibre broadband internet?
Sends computer information coded as pulses of light along underground optical fibres
This technology utilizes total internal reflection to transmit data efficiently.
