Reflection and Refraction

Question 1

Reflection occurs when:

Answer 1

A wave hits a boundary between 2 media (more than one medium) and does not pass through, but instead stays in the original medium

Question 2

Refraction occurs when:

Answer 2

A wave passes a boundary between 2 different transparent media and undergoes a change in direction

Question 2

What is the law of reflection?

Answer 2

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

Question 3

What is the angle of incidence?

Answer 3

The angle of the wave approaching the boundary

Question 4

What is the angle of reflection?

Answer 4

The angle of the wave leaving the boundary

Question 5

How do you draw a reflection ray diagram?

Answer 5

Draw the Reflecting Surface: Create a straight line for the mirror.
Draw the Incident Ray: Add an arrow approaching the mirror, labeled “Incident Ray.”
Mark the Point of Incidence: Label the point where the ray hits the mirror as “P.”
Draw the Normal Line: Draw a dashed perpendicular line (the normal) at point P.
Measure the Angle of Incidence: Use a protractor to measure the angle between the incident ray and the normal
Draw the Reflected Ray: From point P, draw an arrow away from the mirror at the same angle as i

Question 6

How do you draw a Refraction ray diagram?

Answer 6

Draw the Boundary: Create a straight line to represent the interface between two media (e.g., air and water).
Draw the Incident Ray: Add an arrow approaching the boundary, labeled “Incident Ray.”
Mark the Point of Incidence: Label the point where the ray hits the boundary as “P.”
Draw the Normal Line: At point P, draw a dashed perpendicular line (the normal).
Measure the Angle of Incidence: Use a protractor to measure the angle between the incident ray and the normal (label it i)
Draw the Refracted Ray: From point P, draw an arrow into the second medium at an angle, labeled “Refracted Ray.”
Label the Angle of Refraction: Measure the angle between the refracted ray and the normal (label it r).

Question 7

What errors can you make doing a Refraction Ray diagram?

Answer 7

• If the 90 degree lines are drawed incorrectly
• The points for the incoming and reflected beam may be inaccurately marked
  - Use a sharpened pencil and mark in the middle of the beam
• The protractor resolution may make it difficult to read the angles accurately
  -Use a protractor with a higher resolution

Question 8

What is the equation for the refractive index?

Answer 8

n = sin i/ sin r

Question 9

What is the critical angle?

Answer 9

The angle of incidence beyond which all the wave is totally internally reflected when it meets the boundary

Question 10

What is the equation for critical angle and refractive index?

Answer 10

sin c = 1/n

Question 11

Explain why refractive index has no unit?

Answer 11

Refractive index = sin i/ sin r
Sine is a number ratio
Refractive index is also a number ratio

Question 12

State 2 conditions required for TIR:

Answer 12

Must be more optically dense to less optically dense
Angle of incidince > Critical angle