4.6.1.3 Reflection of Waves (physics only)

Question 1

Law of reflection:

Answer 1

angle of incidence = angle of reflection

Question 2

Diffuse reflection:

Answer 2

• reflection that occurs on an irregularly reflecting (rough) surface
• light reflected at different angles
• light is scattered un every direction and no image is formed

Question 3

Specular reflection:

Answer 3

• when light rays are reflected from a smooth surface
• reflections at same angle - gives clear reflection to give clear image

Question 4

What surfaces reflect light well?

Answer 4

• flat surface
• smoother the surface, the stronger the reflected wave

Question 5

What surfaces do not reflect light well?

Answer 5

• rough surfaces scatter the light in all directions so hey appear matt and not reflective

Question 6

Can opaque objects reflect light?

Answer 6

• light will reflect if the object is opaque and is not all absorbed by the material
• the electrons will absorb the light energy, then remit it as a reflected wave

Question 7

When does transmission occur?

Answer 7

• when w aves pass through a transparent/translucent material
• the more transparent, the more light will pass through the material
• light can still refract, but the process of light passing through the material is transmission

Question 8

When is light absorbed?

Answer 8

• if the frequency of the light matches the energy levels of the electrons
• the light will be absorbed by the electrons and not reemitted
• they will be absorbed and then reemitted over time as heat
• so that particular frequency has been absorbed

Question 9

What has been absorbed by a material if it appears green?

Answer 9

if a material appears green, only green light has been reflected, and the rest of the frequencies in visible light have been absorbed

Question 10

What can happen to waves at the boundary between 2 different materials?

Answer 10

• reflection
• absorption (energy of wave absorbed by material)
• transmission
  
  • refraction

Question 11

How wave refracts in more optically dense medium?

Answer 11

• x medium more optically dense so wave has lower velocity in it
• so edge of wave front which enters x medium first slow down
• but part of wave front in other medium continues at higher speed leading to a change in direction of the wave front