refraction 10l

refraction

the change of direction of light when it is entering in a new medium, the speed of light either slowing or speeding up depending on the density of the substance its travelling in

index of refraction

ratio of speed of light in a vacuum to speed of light to a medium

why doesn’t n go below 1?

bc it would imply that the speed of light is going faster than it is in a vacuum which is not possible due to enstian’s theory

c -

fastest light in a vacuum (light can travel)

v -

v and n

speed in a specific medium

v and n are proportional, if n increases, v descreased

apparent depth

Apparent depth refers to the depth at which an object appears to be when viewed from above the surface of a transparent medium (like water or glass).

This is due to the refraction of light as it passes from the water (or another medium) into the air, making the object appear closer to the surface than it actually is.

Explain why the index of refraction of a vacuum is n=1. Use the word “atoms”

and “Snell’s Law

In a vacuum, since n=1n=1, Snell’s Law implies that there is no refraction (or bending) of light as it enters or exits the vacuum from another medium.

This is because there are no atoms in a vacuum to alter the speed or direction of light.

why does n have no units

Because c and v are both speeds and can be expressed in the same units of m/s, the units in the equation divide out, so n has no units.

why does a spoon look discombobulated

Light coming from the part of the spoon below the water’s surface must travel through the water into air.

The speed of light increases as light goes from water into air so, if it hits the water–air boundary at an angle, light will bend away from the normal.

The human brain perceives light to travel in a straight line, so it will project
these light rays backwards to a virtual light
source behind the real spoon

This is similar to how the brain projects
light rays to form a virtual image in a
plane mirror.

why does tir have light bending away from the normal

light needs to bend away from the normal in order for light to reflect back on itself,

because at higher angles of incidence, the light can no longer refract into the less dense medium. Instead, it reflects back into the denser medium, where the angle of incidence and reflection are the same.

why are diamonds so sparkly?

due to the cut of the diamond faces, and the high index of refraction for diamond; results in the total internal reflection of light

Diamonds have a high refractive index, → light bends a lot when it enters the diamond. This causes a small critical angle of 24.4°, so when light hits the diamond at a steep angle, it reflects back inside instead of escaping.

The light can bounce around several times before eventually exiting through the top, creating the sparkling effect that makes diamonds so shiny and appealing.

fibre optics are used for

Fibre optics uses light to send information through a glass cable.

To keep the light from escaping, the cable needs a small critical angle.

This ensures that the light stays inside the cable by reflecting off the walls.

Materials like high-purity glass and certain plastics, like Lucite, have a small critical angle and are used for this purpose.

fibre optics use and endoscopes

• Fibre optics is used in:

  • (phones, computers, TVs)

  • (for lighting the instrument panel in cars)

  • (for viewing inside the body)

• Endoscope: A fibre-optic device used by doctors to check the health of internal organs.

  • It has two fibre-optic bundles:

    • One sends light into the body.

    • The other carries the reflected light back.

• Colonoscopy: A common procedure for people over 50, where an endoscope is used to check for growths in the colon that could lead to cancer.

triangular prism

• A triangular prism also causes total internal reflection.

• The critical angle for glass is about 41.1°. If the angle of incidence is greater than 41.1°, light will reflect completely inside the prism.

• Prisms are more effective than mirrors for reflecting light because they reflect almost 100% of the light, while mirrors lose some light through absorption and wear over time.

• Optical devices like cameras and binoculars use prisms instead of mirrors.

• The light leaving the prism can be 90° or 180° from the incoming light, depending on how the prism is positioned.