Reflection and refraction

Question 1

Describe the images formed by plane mirrors

Answer 1

virtual, upright, laterally inverted and same size

Question 2

Definition of lateral inversion

Answer 2

Lateral inversion is the reversal of a mirror image where the right side of the object appears on the left side behind the mirror.

Question 3

In order to see the full image of a person, the minimum size of the mirror must be what size?

Answer 3

Half of the person’s height. (in reflection, the angle of incidence is equal to angle of reflection)

Question 4

When a plane mirror is rotated through an angle of 5.0º the reflected ray is rotated through on angle of?

Answer 4

10 degrees

Question 5

How does the ancient Chinese mirror work

Answer 5

Little bumps on the mirror causes a mixture of regular and diffused reflection, this leads to a pattern showing

Question 6

Snell’s law

Answer 6

nA sin angle A= nB sin angle B

Question 7

Disappearing glass rod (https://youtu.be/oZupYYZ0YZY)

Answer 7

the liquid has a similar refractive index to glass. so light just passes through and the total internal reflection does not occur （https://drive.google.com/file/d/1S0k5cvZFM5XTqcGSiJ9ZZTlZECJuidVm/view）

Question 8

Factors affecting refractive index

Answer 8

Temperature and types of light

Question 9

Why the thickness of materials will not affect the angle of emergence

Answer 9

the angle is affected by speed of light, speed of light will remain the same when light is moving through the material

Question 10

Why diamonds sparkle

Answer 10

Light rays enter and undergo total internal reflection and exits from the top of the diamond to sparkle

Question 11

Why the light at the end of optical fibre will increase when there is a core with a greater refractive index

Answer 11

The refractive index at core will be high, the critical angle will be smaller and more light rays will undergo total internal reflection within the optical fibre.

Question 12

Calculate the refraction index of the glass relative to acetone for the diagram shown below

Answer 12

acetone/glass

Question 13

Two conditions of total internal reflection

Answer 13

The light ray moves from a more dense medium to a less dense medium. The angle of incidence from the more dense medium must be greater than the critical angle

Question 14

How invisibility works

Answer 14

Divert the light from the eyes