waves (reflection, refraction, sound)

Question 1

What is visible light?

Answer 1

transverse wave

Question 2

What allows us to see most objects?

Answer 2

reflection of visible light which bounces light off them into our eyes

Question 3

What is diffuse reflection?

Answer 3

when light reflects from an uneven surface, the light reflect of at all different angles (paper)

Question 4

What is clear reflection?

Answer 4

when light reflects from an even surface then it’s all reflected at the same angle (mirror)

Question 5

What is the law of reflection?

Answer 5

angle of incidence = angle of reflection

Question 5

What is the normal?

Answer 5

an imaginary line that’s perpendicular to the surface at the point of incidence

Question 6

What is the angle of incidence?

Answer 6

the angle between the incoming wave and the normal

Question 7

How are virtual images formed?

Answer 7

when the light rays bouncing off an object onto a mirror are diverging, so the light from the object appears to be coming from a completely different place

Question 8

What is the angle of reflection?

Answer 8

the angle between the reflected wave and the normal

Question 9

Compare the speed of which EM waves and sound waves travel in denser media/substances

Answer 9

• EM waves travel more slowly in denser media
• Sound waves travel faster in denser substances

Question 10

What happens when a wave crosses a boundary between two substances?

Answer 10

it changes the speed

Question 11

Describe a practical that shows how rays pass through a glass block are refracted twice (1-3)

Answer 11

1. use a light source and a rectangular block of a particular material (glass) resting on top of a piece of paper
2. shine a light ray at an angle into the block. some of the light is reflected, but a lot of it passes through the glass and gets refracted as it does so
3. trace the incident and emergent rays onto the piece of paper and remove the block. you can draw in the refracted ray through the block by joining the ends of the other two rays with a straight line

Question 12

Describe a practical that shows how rays pass through a glass block are refracted twice (4-6)

Answer 12

4. light passes from the air into a block (denser medium), it bends toward the normal because it slows down
5. when light reaches the boundary on the other side of the block, it’s passing into a less dense medium so it speeds up and bends away from the normal
6. the light ray emerges on the other side of the block is now travelling in the same direction it was to begin with - it’s been refracted towards the normal and then back again by the same amount

Question 13

Describe a practical that shows how rays pass through a glass block are refracted twice (1-6)

Answer 13

1. use a light source and a rectangular block of a particular material (glass) resting on top of a piece of paper
2. shine a light ray at an angle into the block. some of the light is reflected, but a lot of it passes through the glass and gets refracted as it does so
3. trace the incident and emergent rays onto the piece of paper and remove the block. you can draw in the refracted ray through the block by joining the ends of the other two rays with a straight line
4. light passes from the air into a block (denser medium), it bends toward the normal because it slows down
5. when light reaches the boundary on the other side of the block, it’s passing into a less dense medium so it speeds up and bends away from the normal
6. the light ray emerges on the other side of the block is now travelling in the same direction it was to begin with - it’s been refracted towards the normal and then back again by the same amount

Question 14

What do triangular prisms disperse?

Answer 14

white light then disperses into different colours

Question 15

What happens when the white light leaves the prism?

Answer 15

the white light is separated into its component colours - red, orange, yellow, green, blue and violet (rainbow effect)