Light

Light

Light

Light travels as waves.

Light travels in straight lines, so if you have to represent a ray of light in a drawing, always use a ruler.

Unlike sound waves, light waves can travel through a vacuum (empty space). They do not need a substance to travel through, but they can travel through transparent and translucent substances.

• Light travels extremely quickly. Its maximum speed is approximately 300,000,000 m/s, when it travels through a vacuum.

  The very large difference between the speed of light in air (almost 300,000,000 m/s) and the speed of sound in air (343 m/s) explains why you:

  see lightning before you hear it see a firework explode before you hear it see a distant door slam before you hear it

Reflection of Light

A ray diagram shows how light travels, including what happens when it reaches a surface. In a ray diagram, you draw each ray as:

a straight line with an arrowhead pointing in the direction that the light travels

Remember to use a ruler and a sharp pencil.

Multiple Choice

Which is the reflected ray?

• A

• B

• C

• D

Multiple Choice

Which is the reflected ray?

• A

• B

• C

• D

Multiple Choice

Which is the reflected ray?

• A

• B

• C

• D

Multiple Choice

Which is the reflected ray?

• A

• B

• C

• D

Multiple Choice

In the diagram, which letter represents the angle of incidence?

• A

• B

• C

• D

Multiple Choice

Law of reflection state that - The angle of incidence is .................. to the angle of reflection.

• equal
• double
• half

Multiple Choice

In the diagram, which letter show reflected light?

• A

• B

• C

• D

Multiple Choice

The following diagram shows the ray diagram when a torch light is torched towards a mirror. Which of the following is the correct reflected ray?

Multiple Choice

How are we able to see?

• Light travels in a circular wave and disappears.

• Light travels in a straight line, reflects off an object, and enters the eyeball.

• Light travels through the object, circles it, then returns to the eyeball.

Multiple Choice

Mirrors work by

• Absorbing the light

• Refracting the light

• Reflecting the light

• Letting the light through

Multiple Choice

Light can pass easily through TRANSPARENT objects. Which object would be transparent.

• shoe

• fishbowl

• me

Multiple Choice

How does light travel?

• In waves

• in a straight path

• does not move

What to do next

Your job is to write a set of rules about reflections.

Your rules should be about the following

Angle of incidence and angle of reflection.

How to draw ray diagrams.

The normal line.

How to represent a mirror.

There is a video in GC shows you how to construct a ray diagram.

Next lesson I would like you to complete the textbook questions on reflection.

I will be available on Teams if you get stuck.