Geometrical Optics

Question 1

draw diagram of reflection.
what is point of incidence?
state laws of reflection?

Question 2

what is a spherical mirror?
if the inside/outside surface of a sphere is polished, then it is a _____ and _______ mirror.

Answer 2

a spherical mirror has the shape of section sliced from the surface of a sphere.
inside concave
outside convex

Question 3

centre of curvature?
radius?
pole?
principal axis?

Question 4

focal length? SI unit
principal focus?

for a lens

Answer 4

the point at which the rays passing parallel to the principle converge in the case of a convex lens and appear to diverge virtually in the case of a concave lens.

pg 60

Question 5

derive spherical mirror equation.

Question 6

what is spherical mirror equation? state formula?

Answer 6

a precise mathematical relationship b/w the object distance & the image distance for a given mirror.
and focal length

Question 7

what is magnification? formula?

mirror

Answer 7

ratio of the height of the image to the height of the object is defined as the magnification.
hi/ ho

Question 8

sign convention of mirror equations?

Answer 8

pg 50

Question 9

when will ray of light bent towards normal? angle of refraction will be less or more?
when will ray of light bent away normal?

Answer 9

when it enters from optically rarer to denser medium
less
vice versa

Question 10

define refraction?
what causes it?

Answer 10

• the change in the direction of light when it pases from one medium through another medium of different densities.
• caused due to change in the speed of light

Question 11

refractive index?
formula?
symbol?
unit?
value for optical medium?

Answer 11

ratio of speed of light in vaccum to the speed of light in specific medium is constant and called index of refraction.
n = c / v
n
unitless
always greater or = 1

c = speed of light in vacuum 3 x 10 ^8 m/s

Question 12

what does refractive index tell us?
value of c?

Answer 12

large value equals higher bending of light.

c = speed of light in vacuum 3 x 10 ^8 m/s

Question 13

conditions for TIR?

Answer 13

2

Question 14

what is TIR?

Answer 14

when incident angle is greater than critical angle, all the incident light is reflected at the boundry back into the optically denser medium.

Question 15

how to derive equation for cirtical angle?

Answer 15

use snell’s law
θ1 = θc
θ2 = 90
sinθc = n2/n1

pg 56

Question 16

parts of optical fibre?
how light doesn’t get out of boundry?what protects the core from what?
how tir used in light propagation through optical fibres?

Answer 16

boundry between the core and cladding

Question 17

what is angle of deviation? draw diagram to demonstrate.

Answer 17

the change in the direction of light as it passes thorugh the glass is called its deviation & is measured as angle of deviation. θ dev

Question 18

what is dispersion of light?
why does it happen?
refractive index is greater and smaller for ____ light?

Answer 18

pg 58

Question 19

what is lens?
types?
shape of types? why are they called that?

Question 20

what is optical centre?
centre of curvature of lens?
focal length of lens?
what is the lens equation?

this is for lenses

Answer 20

centre point of lens O
no real so 2F is used
distance from optical centre to focal point
mathematical relationship b/w the object distance & the image distance for a given lens.

pg 60

Question 21

describe the passage of light through convex and concave lens? by drawing a diagram

Answer 21

pg 60

Question 22

what does lens equation do?

Answer 22

pg 62

Question 23

sign convention for lenses
focal length of convex lens?
if object is on the left side of the lens?
sign when image is on the left side of the lens or same side as the object

Answer 23

+
+
-

pg 63

Question 24

define power of a lens? unit? formula

Answer 24

the degree of convergence or divergence of light falling on lens is called power of lens Diopters or meter inverse
D= 1/f

f = focal length

Question 25

what is magnfiying power? formula? unit? symbol?

Answer 25

pg 65 unitless

Question 26

what is resolving power?

Question 27

what should be done for clear image? what is accommodation? what is focal point of the eye? when are ciliary muscles relaxed? what happens to the lens? when are they contracted? what happens to the lens?

Answer 27

image must be on light sensitive retina process of adjusting the eye's focal length. the retina | pg 67

Question 28

what is near point? aka?

Answer 28

the shortest distance at which the eye can focus a sharp image of an object. for young adults 25 cm | least distance of distinct vision

Question 29

what is short-sightedness? scientific name? where is the image formed? what is done to fix it? which lens? why?

Answer 29

myopia the images of distant objects is focused in front of retina concave/ diverging lens

Question 30

what is long-sightedness? scientific name? where is the image formed? what is done to fix it? which lens? why?

Answer 30

hyperopia convex/ converging lens to converge at retina and not beyond it

Question 31

draw ray diagram of simple microscope and state its resolving power? formula for angula magnifiction for 2 things?

Answer 31

pg 69

Question 32

compound micrscope magnification relation? name the terms? reasons for the formula? what will the answer of relation tell us?

Answer 32

how many times the image has been magnified

Question 33

draw ray diagram of telescope and mention its magnifying power? explain the formula?

Question 34

state Snell's law and formula for it? label constant of proportionality is _______. what is formula when incident medium is air?

Answer 34

The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for the pair of the given media. n1 sinθ1 = n2 sinθ2 same as refractive index when incident medium is air or vacuum

Question 35

if light is moving from denser to rarer medium. will refracted or incident ray be greater?

Answer 35

refracted ray cz it'll bend away from normal pg 55

Question 36

describe the passage of light through parallel sided transparent material.

Answer 36

pg 52

Question 37

how can we know the nature of the image while solving? | for mirrors ## Footnote for lens keep in mind the sign convention for lenses

Answer 37

1. first check if its convex or concave 2. in di if its - then image is behind the mirror. (virtual) 3. if M is + then image is upright/erect 4. then compare ho & hi if it becomes smaller that means that image is diminshed vice versa. | u can also use the methods to see if the sign of ur ans r correct or not ## Footnote but a convex mirror will always form virtual, upright, & diminished images.

Question 38

rearrange mirror formula to find distance of image. why objects in the _______ mirror are closer than they appear?

Answer 38

pg 50 convex cz convex mirror produces an image that is reduced in size, which make the objects look as if its farther away pg 51

Question 39

the magnification of a convex mirror is always ________, but that of a concave mirror ______________. concave mirror can never form ________ image.

Answer 39

positive may be both +ve & -ve virtual, erect, & diminished atst | ved

Question 40

concave **mirror** forms ________ image. convex **mirror** forms ________ image

Answer 40

A concave mirror can form 2 different types of images depending on where the object is placed relative to the mirror: real & virtual A convex mirror always forms virtual, upright, & diminished images, irrespective of the position of the object.