physics - light

Question 1

What is light?

Answer 1

Light is a form of energy that travels in waves and can be seen by the human eye.

Question 2

True or False: Light can travel through a vacuum.

Answer 2

True.

Question 3

What is the speed of light in a vacuum?

Answer 3

Approximately 300,000,000 metres per second (km/s).

Question 4

Fill in the blank: Light behaves as both a ______ and a ______.

Answer 4

wave; particle

Question 5

What is the name of the phenomenon where light bends when it passes from one medium to another?

Answer 5

Refraction.

Question 6

What is the angle of incidence?

Answer 6

The angle between the incident ray and the normal line at the point of incidence.

Question 7

True or False: White light is made up of multiple colors.

Answer 7

True.

Question 8

What tool is commonly used to separate white light into its component colors?

Answer 8

A prism.

Question 9

Multiple Choice: Which color of light has the shortest wavelength? A) Red B) Green C) Blue D) Violet

Answer 9

D) Violet.

Question 10

What is reflection of light?

Answer 10

Reflection is the bouncing back of light when it hits a surface.

Question 11

Fill in the blank: The law of reflection states that the angle of incidence is equal to the angle of ______.

Answer 11

reflection.

Question 12

What is a convex lens?

Answer 12

A lens that is thicker in the middle than at the edges and converges light rays.

Question 13

What happens to light when it passes through a concave lens?

Answer 13

It diverges or spreads out.

Question 14

True or False: Shadows are formed when light is blocked by an object.

Answer 14

True

Question 15

Fill in the blank: Light travels in ______.

Answer 15

straight lines

Question 16

What is a ray diagram?

Answer 16

A diagram that shows the path of light rays as they travel to and from objects.

Question 17

True or False: All materials can transmit light.

Answer 17

False

Question 18

What is the term for materials that do not allow light to pass through?

Answer 18

Opaque

Question 19

What is the difference between transparent and translucent materials?

Answer 19

Transparent materials allow light to pass through clearly, while translucent materials allow some light to pass but scatter it.

Question 20

What is a shadow?

Answer 20

A dark area created when an object blocks light.

Question 21

Multiple Choice: Which of the following is NOT a property of light? A) It can be reflected B) It can be absorbed C) It can be created by sound D) It can be refracted

Answer 21

C) It can be created by sound

Question 22

How can we see luminous objects?

Answer 22

We can see luminous objects because they give off light.

Question 23

How can we see non-luminous objects?

Answer 23

We can see non-luminous objects because light bounces off of them.

Question 24

Describe the effect of concave mirrors.

Answer 24

A concave mirror is a curved mirror that bends inward. It reflects light inward toward a single point called the focus.

Question 25

Describe the effect of convex mirrors.

Answer 25

A convex mirror is a curved mirror that bends outward. It causes light rays to spread out (diverge) after reflecting.

Question 26

Describe what TIR (Total Internal Reflection) is.

Answer 26

Total Internal Reflection where all the light is reflected back inside a material, instead of passing through the boundary between two materials.

Question 27

What is meant by the critical angle?

Answer 27

It’s the smallest angle (measured inside the denser material) at which light is completely reflected back into that material — instead of refracting (bending) out into the less dense material.

Question 28

Josie sees the firework explode before she hears the bang. Why?

Answer 28

Light travels faster in the atmosphere than how fast sound travels in the atmosphere.

Question 29

State where the light comes from so you can see the Moon.

Answer 29

The Moon reflects sunlight as it doesn't make it's own.

Question 30

What is meant by diffuse reflection?

Answer 30

The light is scattered e.g a rock.

Question 31

What is meant by specular reflection?

Answer 31

The light is reflected uniformly e.g glass.

Question 32

When does TIR occur?

Answer 32

If light is shone past a certain angle.

Question 33

True or false: fibre optics use TIR.

Answer 33

True. Light and infrared radiation carries information down thin but solid plastic fibres.

Question 34

List examples of what fibre optics are used for.

Answer 34

aesthetic purposes, for communication, seeing into a human body with an endoscope.

Question 35

What is refraction?

Answer 35

Refraction is the change in speed of a wave due to a change in the material that results in a change of direction.

Question 36

What is the order of the least bent to most bent for the rainbow colours when hitting an angle?

Answer 36

Red, orange, yellow, green, blue, indigo, violet.

Question 37

List all the formulas to make colours from the rainbow colours.

Answer 37

Magenta = blue and red Cyan = blue and green Yellow = red and green White = all colours mixed

Question 38

Explain why only three colours are needed to fully show all colours on a TV screen.

Answer 38

Red, blue and green are the only colours needed as when they mix in their formulas, they produce secondary colours.

Question 39

If the critical angle is 71 degrees and the angle of incidence is 63 degrees, would it be labelled as refract or TIR?

Answer 39

refract.

Question 40

If the critical angle is 83 degrees and the angle of incidence is 97 degrees, would it be labelled as refract or TIR?

Answer 40

TIR.

Question 41

If the critical angle and angle of incidence both measure 50 degrees, what are they labelled as?

Answer 41

refract along the surface.

Question 42

How is reflection from a rough and smooth object similar and different?

Answer 42

The light rays still bounce off the material and produce light. Rough means a diffuse reflection and smooth means a specular reflection.

Question 43

State the law of reflection.

Answer 43

angle of incidence = angle of reflection.

Question 44

What is dispersion and what causes light to disperse?

Answer 44

Dispersion happens because different colours of light travel at different speeds in a medium other than a vacuum. This causes each colour to bend (refract) by a different amount when entering or exiting the medium.

Question 45

When does refraction occur?

Answer 45

When the angle where the light ray hits is smaller than the critical angle.