Science : Light and Optics Unit

This is the official light and optics unit review

Light is a ————— and a ——————

wave and a particle

how do we know light is a wave

because of its interacting light beams can create interference patterns

what are light particles called

photons

how is light a particle

Photons bump into
particles in solar cells, making charged particles move, which produces an electric current

what are the three light bulbs called

Incandescent Light Bulbs
Compact Florescent Light bulbs (CFL)
Light Emitting Diode (LED)

Are Incandescent light bulbs good???

no, it produce a lot of wasted heat, which wastes electricity and makes them inefficient

Are CFL light bulbs good???

they are okay but they tend to explode and are made with special gases, hot to the touch

are LED light bulbs good??

yes, way more efficient than compact fluorescent
bulbs

what are the three basic principles of light

-Light is a form of energy
- Light can behave like a wave and a particle
- Nothing can travel faster than the speed of
light

What are properties of light

1. Light travels in straight lines
2. Light can be reflected
3. Light can bend
4. Light is a form of energy

what’s Refraction

a bending or a something being distorted ex. pencil in water looks bent

what are examples of light traveling in straight lines?

Beams and Rays

What is the reason we can see everything around us

because light bounces off objects and reflects back to our eyes

What happened as light enters a more or less dense medium?

 If it goes into something thicker, like water, it slows down and bends towards the surface. If it goes into something thinner, like air, it speeds up and bends away from the surface.

How are mirrors and lenses similar? How are they different?

Light reflects off a mirror but light goes straight through a lens

How are a convex and concave mirror different? What happens to light after it reflects off each one?

Concave mirrors: 

• Curved inwards 

• When light hits this mirror it will cause the reflected rays to spread 

• Provides wide angle views 

  Convex mirrors

  • Curved outwards

  • Collects light and focuses it on a central point 

How are convex and concave lenses different? What happens to light after it refracts through each?

Convex: are thicker in the middle and thinner at the edges. They converge light rays to a point, making objects appear larger. 

Concave: are thinner in the middle and thicker at the edges. They diverge light rays, spreading them out and making objects appear smaller.

Why do things appear different under the surface of water?

Because light bends when air and water come in contact ( called refraction) and makes things look closer than they appear underwater 

Know how to interpret a ray diagram (incident ray, normal, reflected ray, etc)

If light hits a mirror in one angle it will be reflected at the exact same angle  The incoming ray is called the incident ray the outgoing ray is called the reflected ray  The normal is right in the middle of the two rays 

What is the Pupil and which camera part goes with it

• The pupil is where light enters the eye 

• Much like a pupil an aperture is an adjustable hole that allows light to enter the camera lens

Lenses 

• They are in both a camera and our eyes which are used to to focus light 

• Human’s are made of flexible tissue the muscles surrounding our eyes change its shape 

• Camera’s are made of glass, they move forward and backward, and produce a backward image

what is the retina

• Retina is a layer of light sensitive cells at the back of the eye containing 2 types of cells called rods and cones. Rods are sensitive to dim light and cones detect colors. The retina sends electrical signals to the brain through our optic nerve

• Cameras have a sensor at the back that act like a retina. It usually contains a charged coupled device which changes into a digital signal

Cornea

- the transparent (clear) front part of the eye that covers the iris and
pupil
- The cornea helps the lens to refracts light
- Also offers protection

Viterous

the transparent (clear) gelatinous (jelly-
like) tissue filling the eyeball behind the
lens
- Light passes through the vitreous on its way
to the retina
- Helps maintain the shape of the eye
- helps absorb shocks to the eye
- keeps the retina properly connected to
the back wall of the eye

Optic nerve

Carries the electrical impulses from the eye to the
brain

10.What is the difference between refracting and reflecting telescopes?

Refracting telescopes use lenses to bend light to form an image.

Reflecting telescopes use mirrors to reflect light to form an image.

How are we able to see things around us? And Images

1. Light reflects off objects and enters the eye through the cornea.

2. Lens focuses the light onto the retina at the back of the eye.

3. The retina has cells called rods and cones that convert the light into electrical signals.

4. These electrical signals travel through the optic nerve to the brain, which processes them into images.