Light 7&8 Flashcards
1
Q
Angle of deviation =
A
Diff btw angle of incidence light and angle of exiting ray
2
Q
…………………lens helps to see things far away
A
Concave
3
Q
What are the 2 types of photoreceptors
A
Rods and cone. Comes are more in no
4
Q
…………. lens helps far sighted people ( who cannot see things close to them)
A
Convex
5
Q
Mirror in which virtual img is magnified
A
Concave mirror
6
Q
What is wave theory
A
The principal by Christian Huygens that light travels in the form of waves
7
Q
Phase velocity =
A
Lambda/ time period
8
Q
Speed of light in glass
A
2x10 raised to8
9
Q
In a kaleidoscope,mirror tilted at an angle of
A
45 degree
10
Q
Refractive index of water
A
1.33
11
Q
No of times light is deflected in a prism
A
2
12
Q
When does optical centre coincide with the geometrical centre
A
If the radii of 2 surfaces are equal
13
Q
Img formed by eyes
A
Real and inverted
14
Q
Refractive index of glass
A
1.5
15
Q
Speed of light in water
A
2.25*10 raised to 8
16
Q
Penumbra is seen outside the …………
A
Umbra
17
Q
What are photoreceptors
A
The cells of retina that respond to light
18
Q
Relation btw focal length and radius of curvature
A
2F=R
19
Q
Eyes are ………… lens
A
Convex
20
Q
Where is retina situated
A
Behind the eyes
21
Q
Examples of translucent obj
A
Froasted or grounded glass,greased paper,paraffin wax
22
Q
The white part of a eye
A
Sclera
23
Q
Iris contains
A
Pupil
24
Q
Pupil can
A
Contract and relax
25
Waves energy is directly proportional to
Amplitude sq
26
Intense inversely proportional to
radius sq (distance)
27
Shorter the wavelength of a wave
More the energy and viceversa
28
Objects after getting energy one way to emit it is in the form of
Light as it is a form of energy
29
Objects which are hotter emit waves with
Higher energy that means shorter wavelength
30
Even humans emit light but it is in the
Far infrared spectrum
31
Interference is just
Overlapping of two waves
32
Main 2 types of interference
Constructive interference
| Destructive interference
33
In constructive interference the two waves join together to make the
Amplitude increased
34
In a destructive interference two waves -
Cancel each other's effect
35
The electrons energy determines
where it revolves around the nucleus
36
Increase in electron energy results in increase in distance from
Nucleus
37
Above the nucleus theoretical there is a ladder
Where electrons are Situated
38
The more higher electrons are situated in a ladder the more
Energy
39
Electrons can go higher in the ladder if it gets
Energy
40
How does electrons get energy
Through light
41
If the electrons decide to come down to a lower step in the ladder
It emits light as it is a form of energy
| But more energy shorter wavelength and this can determine the color of the light emitted.
42
In Different substances when an electron comes down in the ladder it emits different amounts of energy so
As based on amount of energy emitted by an electron, color of wave is determined by wavelength which is determined by the energy.
So different substances emit different colours
43
Basically as different substances emit different wavelengths (based on energy)of light when an electron goes down. This helps in understanding what celestial objects are made of based on the color they emit.
This is done by spectrometer which can precisely measure wavelength of light emitted by an object and thus make out what it is made of.
This helped us in understanding what planets many light yrs away are made of
44
Power of lens is
1/ focal length
45
Power of lens unit
Diopter
46
Mirror formula -
1/u+1/v=1/f
U - object distance
V - image distance
F - focal length
47
Magnification of an object is
Height of image / height of object
OR
Image distance / object distance
If the image is virtual - magnification - positive
If the image is real - magnification - negative
48
According to Huygens principle
Every point of a wave can be treated as a source of another wave that spreads out periodically
49
Planck’s constant
6.6 x 10*-34 Joule seconds (JS)
50
Optics is divided into three parts
Geometrical optics
Wave optics
Quantum optics
51
Geometrical optics also called
Ray optics
Deals with the refraction and reflection of light
52
Wave optics also called
Physical optics
Deals with NATURE of light and effects like diffraction,polarisation,interference etc.
53
Quantum optics ?
Deals with INTERACTION of light with atomic entities.
| E.g. photo electric effect , atomic excitation
54
Particle nature of light is explained by
Newton’s corpuscular theory
55
Newton’s corpuscular theory
According to Newton , light travels in space as a stream of very small particles called corpuscles.
It failed to explain interference and diffraction of light.
56
Wave theory of light was published by
Christian Huygen
It failed to explain photo electric effect of light
57
Quantum theory of light was given by
Planck
58
Rest mass of photon is
0
59
3 theories about light
Corpuscular theory by Newton
Wave theory by Christian Huygens
Quantum theory by Planck
60
According to quantum theory
Both light and matter consists of tiny particles that have wavelike properties.
Only when particles are small enough, they show their wave properties
Light composed of particles called(energy packets)
Matter consists of electrons, protons,neutrons
Particles of light are very small , so exhibits wave like properties.
This quantum theory satisfies every property of light by saying light has a dual nature as a particle and a wave.
61
Visible light has a wavelength of
400-750 nm
62
White light ?
Light that contains all frequencies in the visible region.
63
Quantum mechanics
A mathematical model that describes the behaviour of particles on an atomic scale.
It tells that matter and energy are quantised ; they come in small discrete packets.
64
Photon definition
It is the quantum of electromagnetic radiation.
The term quantum is the smallest elemental unit of a quantity.
So one quantum of an electromagnetic radiation is called a photon.
Plural of quantum - quanta
65
Photo electric effect
When light strikes a metal it causes an electron to be ejected from it.
66
Energy of a photon in a wave of light
E = h x f
h - Planck’s constant
f - frequency
Total energy of the electromagnetic wave would be the sum of energy of all the photons
67
Energy of a photon is so small ; it is measured in
eV - electron volts
1 eV = 1.6 x 10* -19 Js
68
Who explained the nature of photo electric effect
Albert Einstein
69
Both real and virtual images can be
Photographed
70
Focal length of a plane mirror
Infinity
71
Power of a plane mirror is
0
72
Keeping the incident ray fixed ; if the mirror is rotated with an angle of “x” about an axis in the plane of mirror; the reflected ray is rotated through an angle of
“2x”
73
Deviation definition
Angle between the DIRECTIONS of the incident ray and emergent ray.
Angle of deviation = 180 - ( i + r ) = 180 - 2i
74
Reflection of light .............. changes
Amplitude or intensity of light changes
75
A thick plane mirror
Forms multiple images , and out of this the second one is the brightest; after that the intensity of the image decreases.
76
No of images formed formed when object is placed between two mirrors
If -
A) 360/theta is even ; then -1
B) 360/theta is odd -
i) symmetric = -1
ii) asymmetric
C) 360/theta is a fraction then take the integer part
77
Focal plane
A plane passing through the principal focus at right angle to the principal axis.
78
A ray incident parallel to the principal axis (concave and convex mirrors)
Passes through the focus
79
A ray incident through the focus is reflected (concave and convex mirrors)
Parallel to the principal axis
80
A ray incident through the curvature
| concave and convex mirrors
Reflected back along the same path.
81
In a convex mirror if the object is placed at infinity; the image is formed in
The focus.
Highly diminished
82
In a convex mirror if the object is placed between infinity and pole of the mirror ; the image is formed in
Between pole and focus.
Diminished
83
In a concave mirror , if object is placed at infinity ; image is formed at
Focus
Highly diminished
84
In a concave mirror , if object is placed beyond (C); image is formed at
Between F and C
Diminished
85
In a concave mirror , if object is placed at (C); image is formed at
C
Same size
86
In a concave mirror , if object is placed between F and (C); image is formed at
Beyond C
Enlarged
87
In a concave mirror , if object is placed at F ;image is formed at
Infinity
Highly enlarged
88
In a concave mirror , if object is placed between Pole and F ;image is formed
Behind the mirror
Highly enlarged
VIRTUAL
89
If the optical density of a medium is high then the speed of light is
Slow
90
During refraction there is change in
Speed and wavelength changes. Frequency is unchanged.
91
Persistence of vision
1/16 of a second
92
Aqueous humor
Liquid between cornea and lens of the eyes
93
White part of the eye
Sclera
| The remaining is the cornea
94
Inside the cornea -
Iris and pupil are present
95
The lens of the eyes adjust their focal point by the
Contraction and expansion of muscles attached to it. i.e. Ciliary muscles
96
The liquid part found behind the lens in the eyes is called
Vitreous Humor [jelly like]
97
Blind spot of the eye
Point at which the optic nerve leaves from the eye. An image formed at this point is send to the brain.
98
Yellow spot of the eye is also called
Fovea
99
Cornea is protected by t
Thin layer of epithelial cells known as conjunctiva
100
Aqueous humour is just
Water and salt
101
Sclerotic
Thick white opaque fibrous tissue covering the exterior part of the eye ball.
102
Choroid
Dull grey membrane between sclerotic and retina.
| Keeps the interior part of the eye dark by preventing internal reflections.
103
Cornea
Tough and transparent membrane covering the front of the eye.
104
Incandescent bulb
An electric light bulb with a wire filament heated to such a high temperature that it glows with visible light (incandescence).
105
Inner side of periscope is
Blackened
106
The no of images formed by a mirror is
360/θ
If the result is a odd no ; then subtract 1. Also do this if the mirror is placed asymmetrically.
107
Distances measured in the direction of the incident beam of light is considered
Positive
| While dist. measured in the opp direction of the incident ray is considered -ve.
108
Motion picture production
Cinematography
109
Cataract
During old age a membrane forms over the lens , causing it to become a little opaque or hazy.
110
Braille script was invented in
1821
111
Wavelength of visible light spectrum is
400 - 700 nm (approx)
112
Wavelength of ultraviolet spectrum
10 - 400 nm
113
Wavelength of X-rays
.01 - 10 nm
114
What is phase
Position or a point of time in a wave cycle
115
Wavelength of gamma rays
116
Wavelength of infrared spectrum
700 - 10 raised to 6 (nm)
117
Wavelength of microwaves
10 ⁶ - 10 ⁹
118
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
119
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
120
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
121
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
122
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
123
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
124
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
125
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
126
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
127
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
128
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
129
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
130
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
131
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
132
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
133
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
134
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
135
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
136
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
137
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
138
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
139
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
140
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
141
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
142
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
143
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
144
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
145
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
146
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
147
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
148
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
149
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
150
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
151
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
152
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
153
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
154
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
155
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
156
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
157
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
158
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
159
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
160
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
161
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
162
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
163
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
164
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
165
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
166
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
167
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
168
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
169
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
170
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
171
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
172
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
173
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
174
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
175
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
176
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
177
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
178
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
179
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
180
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
181
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
182
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
183
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
184
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
185
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
186
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
187
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
188
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
189
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
190
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
191
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
192
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
193
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
194
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
195
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
196
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
197
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
198
In a convex lens, the position to get a same size image is ..... and the position to get an erect image is .....
At 2F
Between F and optical centre.
199
Wavelength of radio waves
>10 ⁹
