Light

Question 1

Luminous and Non-Luminous objects

Answer 1

Luminous- one that produces light
Non-luminous- one that reflects light

Question 2

Image seen in a Plane Mirror- 4 Properties

Answer 2

Same size
Same distance behind the mirror as the object is in front of the mirror
Image is vertical
Image is laterally inverted

Question 3

Laws of reflection

Answer 3

Angle of incidence equals angle of reflection
Incident ray, reflected ray and the normal lie in the same place.

Question 4

Real and virtual image

Answer 4

Real image- one which can be produced on a screen and is formed by rays that actually pass through it
Virtual Image- one which cannot be formed on a screen and is produced by rays which seem to come from it but do not pass through it.

Question 5

Lateral Inversion

Answer 5

An image that is inverted from left to right, like an image seen in a mirror

Question 6

Refraction and conditions necessary for it to occur

Answer 6

Is the bending of light when it passes from one medium to another medium
1.Angle of incidence greater than 0
2.Needs to move from a material into a different material of different refractive index

Question 7

White light spread into different colors in a prism, Name tis process. Name the list of colors displayed on the screen.

Answer 7

Dispersion
Spectrum

Question 8

Different colors of light travel at different speeds in the glass. Why? In the air which speed do the colors travel at.

Answer 8

The greater amount of refraction, greater change of speed
Red refracted the least, it is slowed the least. Violet refracted the most, slowed down the most travel at the same speed in air.

Question 9

What is a critical angle? Total Internal Reflection to occur requires:

Answer 9

Crit angle- is the angle of incidence which gives an angle of refraction of 90 degrees
１The ray must move from a higher refractive index medium to a lower refractive index medium
2. The angle of incidence is greater than the critical angle.

Question 10

Optical Fibre How does it work?

Answer 10

A ray of light enters and undergoes TIR at a bend, so the light cannot escape and travels along the fiber by a series of TIR’s

Question 11

Describe one use of optical fibers in medicine

Answer 11

Optical fibers are used in medicine to take images and look inside the patients body. It is suitable for this as it delivers light into the body which is sent back by TIR to be viewed by the person, also it is very thin.

Question 12

Two following forms of a lens

Answer 12

Converging- Thicker across the middle, thinner at its edge.
Diverging- Thinner across the middle, thickest at its edge.

Question 13

Parallel rays on a converging Lens and a diverging lens

Answer 13

All rays traveling parallel to the principle axis, converge, and pass through the focal point
All rays traveling parallel to the principle axis, diverge from the focal point

Question 14

Converging diagram- Beyond 2F- Properties of Image, Real life examples

Answer 14

• Diminished
• Real
• Inverted
  Eg. Eye, Camera

Question 15

Converging diagram- At 2F- Properties of Image

Answer 15

• Inverted
• Same height
• Real

Question 16

Converging Diagram- Between 2F and F- Properties of Image, Real life examples

Answer 16

• Magnified
• Inverted
• Real
  E.g. Projector

Question 17

A converging diagram what happens at F

Answer 17

Lines are parallel
No image will form

Question 18

Converging diagram- Between F and O- Properties of image, Real life example

Answer 18

• Magnified
• Virtual
• Upright/Erect
  E.g. Magnifying Glass

Question 19

Furthest point away that the unaided eye can see is called. Nearest point away that the unaided human eye can see is called.

Answer 19

The far point- For a normal eye this is at infinity
The near point- For a normal eye this is 0.25m

Question 20

(Short sight) Myopia what does this cause what is the problem. What glasses are needed to counteract this.

Answer 20

Can see things clearly up close, far things are blurred
Far point much, much closer than infinity, near point closer than 0.25m.
Images formed of objects beyond the persons far point are formed in front of the retina hence it looks blurry.
This is caused if their lenses are too powerful or if their eye is too long.
Diverging lens

Question 21

(Long sight) Hypermetropia what does this cause what is the problem. What glasses are needed to counteract this.

Answer 21

Things far away are clear, short things are blurred. Far point is at infinity, near point much further away than the normal 0.25m
Images formed of objects inside the persons near point are focused behind the retina hence looks blurry.
1. Lens is to weak
2. The eye is too short
Converging lens