Parmar Physics
Parmar Physics
Parmar Physics
&
Relative change in position
↳ What is needed?
>
-
Reference point
· ·
A B
Point of origin
Case 1 Case 2
↳-----------------
N 50 m 50 m
L
↓
Distance covered Distance = 100 m
Displacement = 0
Distance = 50 m
Displacement = 50 m
-
Displacement: vector quantity
>
- Distance: scalar quantity
4
3
- -
↓
1
5m 5m 5m
2 cases
↳ 5 sec 6 sec 3 sec >
- Equal distance in unequal intervals:
↑ ↑
Non-uniform motion
5m 5m 5m
W
~
Wind speed is decreasing after increasing: Retardation
↓
Time involved
- m/km
>
Speed = Distance
Time
↳ s/hr
When motion is non-
uniform
S.I Unit: m/s -
> Represented
↑
Average speed = Total distance
Km/hr >
- m/sec Total time
↳x 5
18
m/s > Km/hr
x 18
5
>
-
Avg. speed = 16m + 16m
4+2
= 32 = 16 m/s
6 3
Speed + Direction = Velocity
Velocity = Displacement
Time
Unit: m/s
Distance Displacement
Speed Velocity
Time
5 m/s 5 m/s
Velocity changing with
direction
Change in velocity = Final speed - Initial speed
Case 1
Initial speed = 0 30 s a = 6 - 0 = 1 = 0.2 m/s
Final speed = 6 m/s 30 5
Case 2
Initial speed = 6 m/s
5s a = 4 - 6 = -2 = -0.4 m/s
Final speed = 4 m/s
5 5
Graph Representation
Slope = speed
Slope = Acceleration
Distance Velocity
Time Time
Area = Motion Area = Displacement
Numerical of Motion in straight line: The ‘UTSAV’ Concept
3 equations of motions
1 v = u + at Horizontal motion u = initial velocity
2 s = ut + 1 at t = time
2 s = distance
3 v - u = 2 as a = acceleration
v = final velocity
Vertical
Horizontal
Final velocity = 0
5 x 60 = 300 s
u=0 5 min
v = 72 km/hr
72 x 5 = 20 m/s
18
a = 20-0 = 20 = 1 m/s
300 300 15
s = ut + 1 at
2
s = 0 + 1 x 1 x (300)
2 15
= 3000 m
s = 3 km
Uniform = speed a =v
r
Centripetal acceleration
A Displacement = 0
100 m
10 s = 100 m
1 min = 60 sec
B
Displacement = velocity
Time
What causes Motion?
↓ Motion is caused due to force
State
↓ L
Rest Motion
Force can:
Bring a rested body to Motion
Jo
-
Concept of forces
H S.I unit of force: Newton
Case 1 Represented as “N” Case 2
-
10 N 10 N 10 N 30 N
> E > E
>
-
>
- a-
= 0 No change in velocity
F
Frictional force
Contact and Non-contact forces Types of forces
Force
Examples:
The dry leaves and fruits falls when we shake a tree
A person sitting in a moving car may be pushed forward when the car
stops abruptly as our legs are in contact with the surface
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X
Works on conservation
of momentum and
Newton’s 3rd law
↓d -
·
Gas expelled out
Conservation of Momentum
40 x 5 0
40 x 5 = (40 + 3) x V
200 = 43 V
V = 4. 65
Friction depends on the smoothness of the surfaces. The force of friction always
opposes the applied forces
Once a satellite has been launched into orbit, the only force governing its motion is the
force of: Force of gravity
S.I unit of Electrostatic force
In 1785, Charles Augustine Coulomb used the calibrate tortion balance to measure the
force between electric charges Where q = charge
F= q q
Constant 4 E
The measure of force that can cause an object to rotate about an axis is called: Torque
Universal Law of Gravitation
Electrostatic Force
mI r mI
qI
C
Both are non-contact r q2
- and conservative ↓
F L M I M2 L
forces
SS
(
rI q 12
q
W
FL
-
Work done is r I
F = G M MI I independent of path
If r2 -
Work done in a close F= 1 q q
Gravitational Constant
path is zero 4 ↑E 2r o
R S.I unit
I
-
q = charge
S.I unit of charge: Coulomb
A
G = Gravitational constant
I T
-
> -
G = Nm
I
(1798) N = G Kg
I
>
-
Kg
-
2
m 2
if / A
T r
Ellipse K
E
First Law: Law of Orbit
Planets move in elliptical orbits with the Sun as a focus
Second law: Law of Area
The line joining the planet and the Sun sweep out equal areas in equal interval of time
Third law: Law of Time Period
Cube of mean distance of a planet from the Sun is proportional to the square of the time
period/orbital speed T r
C
Mercury nearest to Sun: 88 days revolution
Neptune farthest to Sun: 165 yrs revolution
SS
Difference between Mass and Weight
Inertia
Constant R
A
Weight: force by which Earth attracts a mass
Force = m x a
Weight = m x g
RM
Variation in gravity
1. Gravity is more in poles than the equator
PA
Vector quantity
S.I Unit: Newton
C
Pressure: scalar quantity
SS
Invented by
Blaise Pascal
P = Kgm
s m
N
m
R
A
= Kg/ms or N/m
RM
Pressure in Fluids
PA
Buoyant Force
C
Less buoyant force
SS
River water has less
density No salt content
Ice
High buoyant force
Relative Density
Density = Mass
Volume
PA
No unit
Work and Energy
What is work?
S.I unit: Nm/Joule James Prescott Joule
Force cause a displacement
C
1J=1N.1m Scalar quantity
1J=2N.1m
SS
2
1J=1N.2m
2
Displacement
Force
PA
Work
What is Energy?
Energy: Capacity to do work
S.I unit: Joule
Biggest source of energy: Sun
Forms of Energy
Mass
C
Kinetic Energy = 1 m x V
Velocity
2
SS
The energy an object has
because of its motion
K. E = 1 mV
2
R
A
Relation between K.E and Momentum
K. E = 1 m V = (mV) = p = K.E
RM
2m 2m 2m
p = K.E
2m
(2p) = K.E = 4 p
PA
2m 2m
The energy stored in P.E converted to K.E
an object due to its P.E becomes less and K.E keeps
P.E increasing Velocity max
position
Potential Energy K.E
Eg: Gravitational P.E
Energy = mgh
Concept of dams based on this Weight = Force = mg
Work done = Energy = F . S
mgh
C
SS
Scaler
Law of Conservation of Energy
Energy can neither be created, nor be destroyed. It can be converted
from one form to another
Electrical Heat
R
1. Dynamo: Mechanical energy Electrical energy
A
2. Generator: Mechanical energy Electrical energy
3. Motor: Electrical energy Mechanical energy
RM
Scalar quantity
1 HP = 746W 1 kW = 1000 W
1 HP = 0.746 kW
Power = Force x Velocity
P = FV
C
Bulb
Electrical Energy Light + Heat energy
SS
Bulb filament made of tungsten (W)
The lifting of an object up and down the parade of an army, and the free fall of a
heavy object are all examples of: Rectilinear motion
C
SS
b
Medium between
tuning fork and ears
R
A
Types of waves
Sound energy travels in the form of energy
RM
Waves
L
-
Mechanical wave
Non-mechanical wave
Medium is required to No medium is required to
PA
propagate propagate
Ex: Sound waves Ex: Light waves
............
↑
-
↑
R
A
RM
PA
Compression Rarefaction
Particles condensed
More density
C
Wavelength
SS
Characteristics of sound waves
Wavelength
Amplitude
C
SS
Vibrated 1
TimeR
A
time
RM
Time
Vibrated 4
times
PA
C
Supersonic: >1 ; < 5
Hypersonic: Mach > 5
SS
Transonic: Mach = 1
Speed of sound
C
SS
R
A
Repeated sound
RM
reflection
C
If an object executes 10 oscillations per second, then its frequency in kilohertz is
equal to: 0.01
10
SS
1000
The approximate speed of sound in distilled water at 25 C (77 F): 1498 m/s
Sound wave cannot travel through a: wooden hollow pipe placed in vacuum
R
The velocity of sound in air is affected by the change in the: Atmospheric
pressure, moisture, temperature of air
A
Temp Velocity
RM
When the temperature increases the frequency of the sound from an organ pipe
Increases
PA
V=n
1200 = 300 x
=4
SSC GK Batch 2.0 PHYSICS CLASS NOTES
What is light? - It is a form of energy
I
>
It has dual nature Particle and as a form of wave
-
It can be polarised
Reflection of Light
C
When a ray of light approaches a smooth polish surface, and the light ray
...
bounces back
SS
Laws of Reflection
1. The angle of incidence = The angle of reflection
2. Incident ray, reflected ray and normal ray all lie in the same plane
>
-
- Normal
R -
-
-
Reflected ray
A
Incident ray
i= r
E
i r
RM
- k
Reflecting Horizontal
surface perpendicular
PA
Types of Mirror
Plane Mirror
Spherical Mirror Convex Mirror
Concave Mirror
-
Concave Mirror -
Reflecting surfaces =
-
curved inwards
-
L
Convex Mirror
C
SS
C = 2F
R
A
Concave Convex
Mirror Mirror
RM
Types of Image
x x
PA
Plane Mirror
1. Image distance = Object distance
2. Object size = Image size
3. Erect Virtual
4. Laterally inverted: Left Right
Right Left
Image Fromation
of Concave Mirror
C
SS
R
A
Object Image Nature
RM
C
y
SS
+ve
-ve +ve
FR x
A
-ve
Inverted image
-y
Inverted
RM
Numericals
Sign convention
u: object distance -ve (always) R = 2F
PA
v: image distance
Concave: -ve
f: focal length
Convex: +ve
R: radii of curvature
Height of image
Mirror Formula
1+1=1 Magnification = h = v
v u f h u
Height of object
Given:
C
u = -25 cm
f = -15 cm
SS
1+1=1
v u f h = -37.5
4 cm -25
1 + -1 = - 1
v 25 15 37.5 x 4
1=1-1
v 25 15
1=3-5
R
25
h = -6 cm
Enlarged image
A
v 75
1 = -2
Inverted
RM
v 75
-75 = -37.5 cm
2
Uses of Mirror
Concave
PA
Magnifying
Shaving mirror Used in solar furnace
Torchlight
Dentist mirror
Convex Diminishing
Rear view mirror in vehicle
Security reasons In ATMs
Sunglasses
Reflection in street light
Refraction of Light
C
SS
Types of Medium
1. Rare Medium
2. Denser Medium
R Air: rarer
Water
A
Medium with more Glass: denser
Density
RM
i
PA
1 Rare
2 Denser
r
No difference
Bend towards the
normal
i> r
Light ray path is rectilinear
Case C
i
Denser
C
Rarer
r
SS
Bend away from
the normal
i< r
Laws of Refraction
R
1. Incident ray, refracted, ray and normal ray all lie in same plane
2. sin i = constant Given pair of media and light of particular wavelength
A
sin r
Two mediums
RM
Rarer
PA
Denser
Lateral Distance
No refraction if strikes
at 90 i= e
Angle of incidence = angle of emergence
Refractive Index Represented with “n” or “u”
C
SS
R
A
RM
Densest medium
Spherical Lens
Lens is transparent
Forms image through refraction
PA
Centre narrow
Centre bulged Ends wider
Ends narrow
Converging lens
C
Diverging lens
Image Formation
SS
R
A
= Concave Mirror = Convex Mirror
RM
Beyond C (same)
C
SS
R
Image Formation of Concave Lens
A
Same as Convex Mirror
RM
PA
Uses
Concave Lens Convex Lens
In treatment of Myopia In treatment of Hypermetropia
Used as magnifying lens
In camera lens
f = -15 cm
C
u=?
v = -10 cm
SS
Lens formula = 1 - 1 = 1
v u f
Magnification formula = h = v
h u
1=1-1
u v f
R
A
m = -10
1=1 - 1 -30
u -10 -15 m=1
RM
1=1 - 1 3
u 15 10
1 = 2 - 3 = -1
u 30 30 m = 1 object size = image size (same size)
m < 1 h > h (Diminished)
1 m > 1 h < h (Enlarged)
u
PA
u= -30
Power of Lens
Power = 1
1=m
Focal Length
m
+ve -ve Dioptre (S.I unit of power of lens)
Convex Concave
Diffraction: it is bending of light around the corner of an obstacle
Question -10
Convex lens = 5cm
C
Concave lens = 10 cm
Convex lens = 2 cm
When all the focal length is
SS
added what power do we
get?
R
A
RM
PA
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Control lensT
C
D
SS
(
Connected to brain
L
(brain sees the
Aqueous humour
L
object not the eye)
Pupil
R
Eye: Click images/formation
A
Cornea
RM
Outermost part
!
Causes refraction of light
Used in eye donation
Aqueous humour
Provides nourishment to cornea
PA
Iris
Dark muscular structure It also determines colour of the eye
Controls the size of pupil
Pupil
To control the amount of light entering the eye
Lens
focuses the light ray on the retina
:
Retina
It is the spot where image is formed
Here optical energy is converted to electrical energy
C
Blind Spot
Optic nerves meet retina
No image is formed here
SS
Power of Accommodation
Eye can change focal length (situation based) Ciliary muscles
R
A
RM
PA
Defects of Eye
Myopia/Near Sightedness
-
..
Image formed behind the retina
!
Light focuses behind the retina
instead of focusing on the retina
:
Correction: +ve lens Convex lens
Usually occurs above 40 yrs
C
SS
Presbyopia
Lens hardens with age Loses flexibility
Age: 55+
R
Correction: Concave + Convex lens
(Bifocal lens)
A
Glaucoma/Trachoma
Both caused due to increase in eye
RM
pressure
Glaucoma is hereditary
Not curable
-
>
-
Colour Blindness -
IIIIIIIIIII
It is hereditary
Retina made of cone cells and rod cells
Convex lens
Not present in colourblind
people
Refraction of Light by a PRISM
V
·
Hi
L
R 7
Angle of Deviation
- ↓
-VX I'll
D
Wavelength
↓ Wavelength↑ Deviation↓
C
Ray of light away from the normal
SS
Dispersion of White Light in a Glass Prism
R -
-
Highest wavelength
Less deviation
A
Consist of 7 different colours
↑ Decreasing
wavelength
RM
V
↓
More deviation
PA
TRICK
Rich Man in Victor Uses X Gold
Radio Micro
R
Infrared Visible UV rays X-ray Gamma rays
A
waves waves
wavelength
PA
Due to dispersion
C
Refractive index
SS
of different types of
gases In refraction, the actual
position of stars
changes to apparent
position
R
Advance Sunrise and Delayed Sunset
A
RM
PA
C
SS
Blue colour of sky: blue light is scattered more than the other colours because it travels as
shorter, smaller waves
Our sky appears black without atmosphere
R
A
RM
PA
Red colour of Sun during sunrise and sunset: red light scatter the least by the molecules
present in the air, so at sunset and sunrise, the sunlight travels longer path through the
atmosphere to reach our eyes. The blue light catches the most and has been mostly
removed, leaving the red light remaining which reaches our eyes.
More wavelength
C
SS
Tyndall Effect
R >
Colloidal solution scatter the light
- most because the dispersed
A
particles of colloid are bigger and
they defect light
RM
2 1
-
> Red has maximum wavelength and
is least scattered allowing it to
travel long distances without
getting scattered
Total Internal Reflection
-
C
↓
SS
The layer above the ground
gets warmed. The light ray gets
Optical Fibers
ONE LINERS (MCQs)
The materials through which things can be seen are called transparent materials
The reflection on the bathroom mirror, the lake and the glare on pair of glasses are
caused by specular reflection
Gold and copper happen to absorb blue and violet light, leaving the yellow light
C
The phenomenon which deals with scattering of light by molecules of a medium when
SS
they are excited to vibrational energy levels is called Raman Effect
The phenomena in which mountain tops acquired a rose or orange hue around the
sunrise and sunset is called Alpenglow
↳ 19 4)
1 e = 1.6 x 10 Coulomb
-
i=q
↳ S.I unit of charge t
C
q=ixt
q=nxe
is
1 C = n x 1.6 x 10
Id
-
SS
n = 6 x 10 e -
I
Electric current is measured by Ammeter
↑
Current S.I unit: Ampere
R Charge
Current = Charge
Time
A
L W
+ve -ve
RM
↑
Like charges repel each other -
Conductor: is a material that
-
Opposite charges attracts each other conducts electricity/allows electron
to flow through it
PA
Potential Difference
↑
The amount of work done in moving a unit positive charge from one point to other in an
electric field ↓
Measured though: Voltmeter
Potential < V=W · S.I unit: Volt ↑
difference q
L
1 volt: if one Joule of work is done in moving,
Work done to move the one coulomb of charge
charge 1V = 1J &
1C
Ohm’s Law The current flowing in a conductor is directly
By George Simon Ohm in 1827 proportional to the voltage across the conductor,
V I provided all the physical condition and temperature
V = IR remain constant
Resistance
C
S.I unit Ohm ( )
SS
Resistance: the property of a conductor to resist the flow of charge through it
Resistivity/Specific resistance
R L = mho/ohm
R 1 =lm The resistivity of a material is the
A m resistance of a wire of that material
R L m=
PA
A
R= L S.I unit
A
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C
SS
Alloy has greater resistivity than its constituent metals
Types of Materials
electrons
R
Conductor: materials that conduct electricity/allow electric flow through them
Seen in metals
Has free
A
Semi-conductor: they are materials which have conductivity between conductors and non-
conductors or insulator. Eg: Silicon (usually Metalloids)
RM
Insulator: materials that do not allow electricity to pass through them. Eg: Non-metals
such as glass, wood
Series
R R
1 =1 +1 +1
R R R R
R R
R =R +R +R +R
-
Series: same current; different potential difference
-
C
>
-
Red = R ↑ + R I
V = IR
20 + 4 = 24z
SS
6 V = I x 24e
1/6 =I
4 24
/
0.25 A = I
Q. R = 522
&
P.d = 12 V
Current?
; R = 10+ ; R32
= 30
R >
-
Parallelly connected
A
-
V = IR V = IR V = IR
RM
12 = I x 5 12 = I x 10 12 = I x 30
12 = I 1.2 A = I 0.4 A = I
5
2.4 A = I
>
- 2.4 + 1.2 + 0.4 = 4.0 A
1 =1 +1 +1
OR H M
- -
>
-
Rea R R I R3
PA
1 =1+1 +1
- - -
V = IR
R ed 5 10 30
12
/ = I x↓
3
1=6+3+1
I =4A
R ec 30
1 = 10
Rea 30
R = 3I
Heating effect of Electric Current
&
V=W Power = Work Done
q Time
-
Substituting
Electric Power = qV-
C
Electric Power = VI
Heat = Power x t
SS
Heat = VIt
IR x IT
Z
I RT = H
-en
m
↓
RM
Filament made of
Coils in heater made of Nichrome
↓ Tungsten (W)
Alloy of Ni and Cr
-
Fuse
I
Low melting point
-
P = VI
P=I R V = IR
P=V V =I
R R
C
Commercial Unit of Energy
1 unit = 1 kWh
SS
Pxt 1 kW = 1000 W
1000 x 3600s 1 hr = 60 mins
36 x 10 Ws 60 x 60 = 3600 secs
3.6 x 10 J 1 unit
220 V; 50 Hz
R
In electric appliances
A
Live wire: Red
Colour of wire
Neutral: Black
Ground/Earth: Green/Yellow
RM
PA
Magnetic Effect of Electric Current
~
C
SS
Electric current passed through the
>
-
>
wire
/
d
>
-
R
A
V
C
SS
↳
Same poles repel each other Iron fillings align themselves with
-
-
>
Magnetic field lines originate from North Pole
outside the magnet and terminate at South Pole
-
>
Magnetic field line are in the form of closed
loop
PA
>
-
Magnetic field lines never intersect each other
d
L If they insect, there will be
Vector quantity two directions of magnetic
field lines which is not
possible
=>
If magnetic field lines are closer - Magnetic
Field↑
Magnetic Field due to a Current Carrying Conductor
C
Magnetic Field 1
SS
Distance
C
Clockwise Anti-clockwise
SS
Maxwell’s screw rule to find
direction of magnetic field in a
straight current carrying conductor
C
maximum inside the solenoid
It is uniform
SS
Current passed through a
solenoid
If direction of current is
Magnetic field lines outside the
reversed, the direction of
R
magnetic field is also
reversed
solenoid is very weak Considered to
be practically zero
A
Electromagnetic
RM
C
SS
Magnetic field
Force will be Maximum: the angle between the conductor and the magnetic
R
field is 90
C
It is the phenomenon in which
electric current is generated by
charging magnetic fields
SS
Discovered by Michael Faraday in
1831
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Short circuit: it is caused due to breaking of insulation of wires, forming the contact
between live wire and neutral wire
C
One Liners (MCQs)
SS
Device that is used to either break an electric circuit or to complete it: Switch
Gustav Robert Kirchhoff stated that at a junction in electric circuit, the sum of
currents flowing in the junction is equal to the sum of current flowing out of the
junction
R
Wheatstone Bridge is an arrangement of four resistors used for accurate
measurement of resistance
A
RM
The current in the bulb will stop flowing if the circuit is broken
In the symbol of electric cell, the thicker, shorter line represents the: Negative
terminal
Michael Faraday gave the concept of electric field for the first time
The scientist who was awarded an Noble Prize for the services to Theoretical Physics,
and specially for his discovery of Law of Photoelectric Effect: Albert Einstein
E = hv
C
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SS
R
A
RM
PA