Reflection and shit

Question 1

What is a virtual Image?

Answer 1

• -> divergence of rays

- ->cannot be formed on screen

Question 2

What are the characteristics of Reflective Materials?

Answer 2

• ->smooth
• ->shiny
• ->pale
• ->give clear images (specular)

Question 3

What are the Characteristics of Non-Reflective Materials?

Answer 3

• ->rough
• ->dark colours
• ->give DIFFUSE images

Question 4

What is Snell’s Law?

Answer 4

n=sin i/sin r

Question 5

What is the symbol for refractive index?

Answer 5

n

Question 6

Why does a refractive index have no unit?

Answer 6

• ->it is a ratio

- ->as n=sinr/sinr

Question 7

Critical Angle

Answer 7

• ->angle of incidence

- ->when angle of refraction=90

Question 8

equation for critical angle

Answer 8

sinc=1/n

Question 9

Law of Reflection

Answer 9

angle of incidence=angle of reflection

Question 10

Snell’s Law Practical Method

Answer 10

• ->Place a glass block
• ->Draw around block
• ->Draw normal(protractor)
• ->draw lines at 10 degree INTERVALS
• ->Shine ray at lines
• ->Dot point where ray
• ->from line linking points to normal

–>use RANGEof values

Question 11

Snell’s law practical recording

Answer 11

• ->graph

- ->refractive index=gradient

Question 12

How do you find the location of an Image?

Answer 12

• ->object distance=image distance
• ->extend perpendicular line
• ->virtual rays dotted

Question 13

Describe a (virtual) image

Answer 13

• ->laterally inverted

- ->same distance inside mirror

Question 14

Effects of Higher refractive index

Answer 14

• ->more refraction

- ->angle of refraction closer to normal

Question 15

Explain Effects of Higher Refractive index

Answer 15

• ->more likely to be totally internally reflected
• ->critical angle smaller(ri higher)
• ->TiR when i>c
• ->LARGER RANGE of angles

Question 16

When does total internal reflection only occur?

Answer 16

–> ONLY from more optically dense to less optically dense

Question 17

Refraction definition

Answer 17

• ->change of direction

- ->change from one medium to another

Question 18

What is the condition of a Refractive Index?

Answer 18

Must always be bigger than 1

Question 19

uses of TIR

Answer 19

• ->PRISM in periscope
• ->optical fibres
• ->safety reflector
• ->endoscopes
• ->optical fibres
• ->(Viewing) prism in camera

Question 20

What is meant by the term total internal reflection?

Answer 20

• ->The reflection occu. inside the mater.
• ->ALL the light is relect.
• ->occu. inside opt. more dense medium
• -> Incid. angle>critical angle

Question 21

When does the ray not deviate?

Answer 21

• ->When i=0

- ->When the light passes thru. int. at 90 degree

Question 22

Explain what happens in a glass fibre?

Answer 22

• ->Inci. angle larger than critical angle
• -> light reflects at inside
• ->’cus light travels slower in glass