refraction of lens and light

Question 1

when object is at infinity [convex] -

Answer 1

real , inverted , diminished [ almost at a point ]
image is formed at f2
in burning glass

Question 2

when object is at beyond 2f1 [convex]

Answer 2

real inverted diminished
image is formed btw f2 and 2f2
camera lens

Question 3

when object is at 2f1

Answer 3

at 2f2 [formed]
same size , real inverted
in terrestrial telescope

Question 4

when object is at btw 2f1 and f1

Answer 4

at beyond 2f2
magnified real inverted
projector

Question 5

when object is at f1

Answer 5

formed at infinity
highly magnified real inverted
collimator of spectrometer

Question 6

when object is at between lens and f1

Answer 6

on same side behind the object
magnified virtual upright
magnifying glass

Question 7

when object is at infinity [ concave]

Answer 7

at the focus on same side of the lens as the object
virtual upright highly diminished
galilean telescope

Question 8

when object is at any position btw infinity and optical centre in
concave

Answer 8

on same side between focus and optical centre
virtual upright diminished
making spectacles for myopic eye

Question 9

lens formula -

Answer 9

1/v - 1/u = 1/f

Question 10

linear magnification [m] -

Answer 10

length of image / length of object =v/u

Question 11

power -

Answer 11

deviation of the incident light ray produced by a lens on refraction through it is measure of power

Question 12

unit of power

Answer 12

dioptre

Question 13

formula - D

Answer 13

D= 1/f [in metre ]

Question 14

convex lens power is

Answer 14

positive

Question 15

concave lens power is

Answer 15

negative

Question 16

negative height of image = ______

Answer 16

inverted

Question 17

positive height of image = ________

Answer 17

virtual

Question 18

I / O =

Answer 18

I / O = V / U

Question 19

REFRACTIVE INDEX with respect to critical angle is

Answer 19

sin c = 1 / refractive index glass with respect to air

Question 20

sin 42 =

Answer 20

2/3

Question 21

sin 49 =

Answer 21

3/4

Question 22

dependence of critical angle

Answer 22

critical angle increase with increase in wavelength

critical angle increase with increase in temp

Question 23

when will total internal reflection happens

Answer 23

when angle of incidence is greater than critical angle

Question 24

essential condition for total internal reflection

Answer 24

light should move from denser to rarer

angle of incidence should be greater than critical angle for pair of media

Question 25

what is spl in total internal reflection -

Answer 25

100% intensity of light is reflected due to this case total internal reflection is used in binocular , periscope , certain type of camera

Question 26

equilateral prism -

Answer 26

each angle 60 *

Question 27

right angled isosceles prism

Answer 27

45* ,90*, 45*

Question 28

right angled prism -

Answer 28

30* , 90* , 60*

Question 29

right angled isosceles prism used in [90* one ]

Answer 29

periscope

Question 30

right angled isosceles prism [deviate 180*]

Answer 30

binocular and camera to invert image without lose of intensity

Question 30

right angled isosceles prism [deviate 180*]

Answer 30

binocular and camera to invert image without lose of intensity

Question 31

erecting prism used in

Answer 31

slide projector

Question 32

some consequences of total internal reflection -

Answer 32

phenomenon of mirage empty test tube placed in water with its mouth out shines like mirror when seen from outside crack in glass vessel often shines piece of diamond sparkles when viewed from outside certain distance

Question 33

________ used to transmit a light signal over long distance without any lose of energy

Answer 33

optical fibre

Question 34

total internal reflection vs mirror reflection difference

Answer 34

total internal reflection - image is much brighter and remains unchanged even after long time use mirror reflection of mirror image is less bright gradually decrease as silver in mirror becomes old and rough

Question 35

Rarrer to denser -

Answer 35

towards the normal

Question 36

denser to rarrer -

Answer 36

away from the normal

Question 37

intensity of refracted light decrease why?

Answer 37

some part gets reflected

Question 38

deviation means -

Answer 38

the angle between direction of refracted and incident ray

Question 39

snell's law means -

Answer 39

incident ray , refracted ray and the normal at point of incidence all lie in same plane ratio of sin i/ sin r=refractive index

Question 40

wavelength formula

Answer 40

wavelength = V / F , V - SPEED , F - FREQUENCY

Question 41

speed of light in vaccum -

Answer 41

299,792,458 or 3*10^8

Question 42

refractive index formula on basis of speed -

Answer 42

speed of light in vacuum / speed of light in medium - absolute refractive index

Question 43

refractive index is always greater than 1 why?

Answer 43

because always speed of light in any medium is less than speed of light in air

Question 44

refractive index of diamond is 2.41 it means

Answer 44

light travel in air 2.41 times faster than in diamond

Question 45

if refractive index is equal in both medium , what happens ?

Answer 45

speed of light will remain same , light will go without change in its path even when incidence is not 0

Question 46

when light passes undeviated -

Answer 46

when refractive index is equal in both medium | angle of incidence is 0

Question 47

factors affecting refractive index -

Answer 47

less speed in medium as compared to that in air, more refractive index increase in temp speed of light increases refractive index decrease increase wavelength refractive index decrease

Question 48

refractive index respect to medium 2 and 1 -

Answer 48

refractive index respect to medium 2 and 1 - | 1/ refractive index respect to medium 1 and 2

Question 49

lateral displacement -

Answer 49

perpendicular distance btw path of incident ray and emergent ray

Question 50

dependence of lateral displacement -

Answer 50

more refractive index more lateral displacement more thickness more lateral displacement more angle of incidence more lateral displacement

Question 51

light ray of single light -

Answer 51

monochromatic ray

Question 52

deviation becomes minimum when -

Answer 52

angle of incidence is equal to angle of emergent

Question 53

factors affecting angle of deviation -

Answer 53

higher refractive index greater deviation increase in angle of prism increase in deviation decreases with increase in wavelength

Question 54

refractive index with respect to real and apparent depth

Answer 54

refractive index = real depth / apparent depth

Question 55

shift =

Answer 55

real depth * [1-1/ refractive index]

Question 56

dependence of shift -

Answer 56

higher refractive index higher shift thicker the medium higher the shift increase in wavelength shift decrease