Light And Sound

Question 1

Light waves

Answer 1

Transverse, can be reflected and refracted

Question 2

Law of reflection

Answer 2

Angle of incidence (i)= angle of reflection (r)

Question 3

Equipment for Reflection practical

Answer 3

• glass block
• paper
• pencil
• ray box

Question 4

Method for refraction practical

Answer 4

• place the glass box on a sheet of paper and draw around using a pencil
• aim the ray box so a single ray of light passes through the block
• mark points along the path of the ray: before it reaches the block, where it hits the block, where it leaves the block, after it has left the block
• remove the block and connect the point

Question 5

Snell’s law

Answer 5

Refractive index = sin of angle of incidence/ sin angle of reflection
N=sin I/sin r

Question 6

What is Total internal reflection

Answer 6

When light is moving from a denser medium towards a less dense one, instead of being refracted, all of the light is reflected

Question 7

What are the necessary conditions for total internal reflection to occur

Answer 7

• the light must be going from a more dense medium towards a less dense one
• the angle of incidence must be greater than the critical angle

Question 8

Critical angle

Answer 8

The critical angle of a material is related to its refractive index (n)
Sin c = 1/n (refractive index)

Question 9

What is the critical angle

Answer 9

Angle of incidence that provides an angle of refraction of 90 degrees

Question 10

Sound waves

Answer 10

Longitudinal, can be reflected and refracted