2. Reflection of Light

Question 1

what can happen to light when it meets an interface between two media

Answer 1

absorbed
transmitted
reflected

Question 2

laws of reflection

Answer 2

incident ray, reflected ray and the normal to the reflecting surface all lie in the same plane

Question 3

angle of incidence

Answer 3

equals the angle of reflection

Question 4

parallel light and irregular surface

Answer 4

gets scattered in many directions –> diffuse reflection

Question 5

brain and ‘images’

Answer 5

brain assumes that an objected is situated in the direction form which lights enters the eye BUT if the observer actually goes to the point of the image – there is no real image

Question 6

virtual images

Answer 6

could not be captured on a screen
((usually dotted line

Question 7

real images

Answer 7

could be captured on a screen

Question 8

image formed at a plane surface is

Answer 8

erect
virtual
laterally inverted

Question 9

if a plane mirror is rotated

Answer 9

the reflected ray is deviate through an angle equal to TWICE the anlge of ROTATION of the mirror

Question 10

spherical mirror

Answer 10

is the reflecting surface is a portion of a sphere

Question 11

if the reflecting surface lies on the inside of the curve

Answer 11

concave

Question 12

if the reflecting surface lies on the outside of the curve

Answer 12

convex

Question 13

centre of curvature

Answer 13

= C
the centre of the circle (is the reflecting surface was extended to a whole circle)

Question 14

pole of the mirror

Answer 14

= p
centre of the reflecting surface

Question 15

radius of curvature

Answer 15

= r
distance between C to P

Question 16

axis

Answer 16

axis is any line passing through the centre of curvature and striking the mirror

Question 17

principle axis

Answer 17

an axis passing through the centre curvature and striking the mirror AT THE POLE

Question 18

rays parallel to the principle axis are reflected

Answer 18

concave = towards the principal focus
convex = away from the principal focus

Question 19

principal focus

Answer 19

= F
this is the mid point of r (radius of curvature)
mid point between C and P

Question 20

focal length

Answer 20

= f (lower case)
distance between F and P
half the radius of the curvature

Question 21

an object situated on the principal axis at infinity

Answer 21

is formed on at the principal focus

Question 22

image formed by a concave mirror

Answer 22

real (infrontof lens)

Question 23

image formed by a convex mirror

Answer 23

virtual (behind lens)

Question 24

how to construct a ray diagram

Answer 24

1. Ray parallel to principal axis reflected to/away from principal focus
2. Ray from top of object passing through the centre of curvature and reflected back

Question 25

CONCAVE mirror object outside C

Answer 25

real inverted diminished

Question 26

CONCAVE mirror object between C and P

Answer 26

real inverted enlarged

Question 27

CONCAVE mirror object inside principal focus

Answer 27

erect virtual enlarged

Question 28

CONVEX mirror object at any point

Answer 28

virtual erect diminished

Question 29

position of the image formed calculation

Answer 29

1/v - 1/u = 1/f = 2/r u = distance of the object from the mirror v = distance if the image from mirror f = focal length r = radius of curvature

Question 30

definition of magnification

Answer 30

ratio of image size to object size

Question 31

magnification calculation

Answer 31

i / o = - (v / u) i = image size o = object size v = distance of object from mirror u = distance of image from mirror

Question 32

sign convention

Answer 32

distances measured in the same direction as the incident lgiht are positive against the direction are negative

Question 33

all distances are measured

Answer 33

from the pole of the mirror to the point in questions

Question 34

image size is postive for

Answer 34

erect images (above the principal axis)

Question 35

image size is negative for

Answer 35

inverted images (below the prinicpal axis)

Question 36

Purkijne image I

Answer 36

Anterior cornea Image - erect and virtual Use - squint, keratometer

Question 37

Purkijne image II

Answer 37

Posterior cornea Image - erect and virtual Use - specular microscopy

Question 38

Purkijne image III

Answer 38

Anterior lens Image - erect and virtual Use - lens in accom

Question 39

Purkijne image IV

Answer 39

Posterior lens Image - real and inverted Use - lens in accom