Light

Question 1

incident ray

Answer 1

a ray of light arriving at a surface

Question 2

reflected ray

Answer 2

a ray of light which has been reflected from a surface

Question 3

ray diagram

Answer 3

a diagram showing the path of rays of light

Question 4

normal

Answer 4

line drawn at right angles to a surface at the point where a ray hits the surface

Question 5

image

Answer 5

what we see when we view an object by means of reflected rays
in plain mirrors:
- always the same size
- same distance behind the mirror as the object is in front of it
- directly in line with the object

Question 6

plane mirror

Answer 6

a mirror with a flat reflective surface

Question 7

laterally inverted

Answer 7

an image in which left and right have been reversed

Question 8

real image

Answer 8

an image that can be formed on a screen

Question 9

virtual rays

Answer 9

rays that appear to be there but arent because theyre in the mirror

Question 10

virtual image

Answer 10

an image that cannot be formed on a screen

Question 11

when does total internal reflection occur?

Answer 11

When the incidence angle is larger than the critical angle

Question 12

what is the angle of refraction when the incidence angle is equal to the critical angle?

Answer 12

90

Question 13

critical angle

Answer 13

the angle of incidence which leads to the refraction of 90 degrees

Question 14

total internal reflection

Answer 14

when light doesnt refract, only reflects

Question 15

symbol with outgoing lines

Answer 15

convex, converging

Question 16

symbol with ingoing lines

Answer 16

concave, diverging

Question 17

object is placed more than 2f (converging)

Answer 17

image is smaller than object

Question 18

object is at 2f (converging)

Answer 18

same size and distance

Question 19

object is between 2f and f (converging)

Answer 19

the image gets larger

Question 20

object is at f (converging)

Answer 20

no image is formed

Question 21

object is between f and lens (converging)

Answer 21

virtual image is formed

Question 22

refractive index formulas

Answer 22

n = sini/sinr

n = 1/sinc

Question 23

relationship between angle of reflection and angle of incidence

Answer 23

the angle of incidence equals the angle of reflection

Question 24

shape of converging/convex lens

Answer 24

leaf-like. Thicker at center.

(CONV = CONV)

Question 25

shape of diverging/concave lens

Answer 25

hourglass. Thicker around the edges.

(conCAVE = cave opening-like)

Question 26

Concave lens uses in terms of eye-sight

Answer 26

Is used to correct short-sightness - when the distance between the eye’s lens and retina is longer than it should be. Concave lens reduces the refraction of light and lengthens the focal length so that the image is formed on the retina.

Question 27

Convex lens uses in terms of eye-sight

Answer 27

Is used to correct long-sightness - when the distance between the eye’s lens and retina is too short, as a result of which the focal point lies behind the retina. Convex lenses increase refraction and accordingly reduce the focal length.

Question 28

How do convex/converging lens focus light?

Answer 28

Convex lens focuses light rays to a specific point

Question 29

How do concave/diverging lens focus light?

Answer 29

concave lens diverges the light rays

Question 30

use of optical fibres

Answer 30

long-distance and high performance data networking - telecommunication, such as internet, televison and telephones.

Question 31

How do optical fibres work?

Answer 31

Light travels from one end to the other by total internal reflection.They can carry enormous amounts of information in light pulses trapped inside them.

Question 32

use of optical fibres in medicine

Answer 32

endoscopy - to view internal organ part or for keyhole surgery