first year physics by asadullah talpur

8/6/2019 first year physics by asadullah talpur

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Physics definitionsChapter 1

The Scope of Physics

(What we have created, it is not in vain there are signs for theman of understanding Al-Quran)

1. Physics: - it is the branch of science that deals with the study of matter and energy andtheir mutual interactions between them. OR

THE STUDY OF NATURE OF THE NATURE IS CALLED PHYSICS

2. Energy: - the ability/capacity to do work is called energy.

3. Work: - work is said to be done on a body when, by applying force it attains some

displacement.

4. Force: - it is the agency that changes or tries to change the state of rest or motion of the

body.

5. Displacement: - the shortest straight distance between the two points, having a

particular direction. Or the change in position of the body.

6. Distance: - it is the length of the path (curved/line) described by an object moving in

space.

7. Mechanics: - mechanics is the branch of physics that deals with the bodies in rest or

motion under forces.

8. Fundamental quantity: - the quantity, which cannot be resolved into more

fundamental quantities.

9. Derived quantity: - quantities, which are, expressed as some combination of

fundamental quantities.

10. Proportional quantities: - such these quantities are dependent on each other; the

change in one quantity causes the change in another quantity.

11. Directly proportional quantities: - the quantities in which increase in the amount of

one quantity results in the increase of other quantity and the decrease in one quantity affects

the reduction in another quantity.


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12. Inversely proportional quantities: - in such a case the increase in the amount of one

quantity leads to the decrease of the other quantity and vice versa.

13. Constant of proportionality: - when proportionality sign is removed, the =sign is

applied only after putting a constant that is determined experimentally and is called

constant of proportionality.

14. System of units: - a set of fundamental and derived units is called a system of units.

15. Mean solar day: - a mean solar day is the time interval between two successive

overhead appearances of the sun.

16. Second: - it is the duration in which Cesium CS133 atom completes 9192631770

transitions between two hyperfine levels.

17. Meter: - it is the path/distance covered by light or the object moving with the speed of

light in 1/c seconds (c= 3*108

).

18. Ampere: - one ampere is the amount of current, witch if maintained in two straight

conductors of infinite length and negligible area of cross section and placed one meter apart

in space would exert a force of 2*10-8 on each other.

19. Kelvin: - It is 1/273. 16 of the thermodynamic temperature of the triple point of water.

(Triple point is the temperature where all the three states of water co-exist)

20. Mole: - the gram atomic mass, gram molecular mass or gram formula mass of any

substance, which contains 6.02*1023 particles

21. Kilogram: - one kilogram is the mass of the platinium-irradium cylinder at 0 C kept atBIPM near Paris.

22. Dimension: - it is use to denote the nature of the physical quantities.

Chapter 2

SCALARS AND VECTORS

(The more I want to get some thing done, the less I call it workRichard Bach)

23. Scalars: - physical quantities which dont have direction but only magnitude and a

suitable unit


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24. Vectors: - the physical quantities, having both the direction and magnitude.

25. Particle: - an object of negligible size and constant mass is referred to as particle or

body. This idea represents a simple model of a real physical situation.

26. Resultant vector: - it is the vector, obtained as a result of the combination of vectors.

27. Component vector: - when a vector acts on a body it may be splited into two or more

vectors, called component vectors. Generally a vector is resolved into its rectangular

components.

28. Rectangular components of a vector: - the components of a vector, which are inclinedat the angle of 90.

29. Unit vector: a vector whose magnitude is one is called unit vector.

30. Null vector: - a null vector is that vector whose magnitude is zero.

31. Free vector: - a free vector is that vector which can be displaced parallel by itself andapplied to any point.

32. Position vector: - a position vector is that vector which is used to specify position of a

body or anything with respect to a fixed point, such as the origin of coordinate system (it

means that it tells you that how far and in what direction is a point from the origin of acoordinate system)

33. Negative of a vector: - a vector whose magnitude is same but the direction is opposite.

34. Parallelogram law: - if sides of a parallelogram represents to vectors to be added, thendiagonal of the parallelogram represents their resultant.

35. Resolution of vectors: - the process of splitting a vector into its two or morecomponents.

36. Composition of vectors: - the process of joining two or more vectors to get a single

resultant vector is called composition of vectors.

37. Scalar or dot product: - if multiplication of two vectors results in a scalar quantitythen such type of multiplication of vectors is called scalar or dot product.

38. Vector or cross product: - if multiplication of two vectors results in a vector quantity,

then such type of multiplication is called vector product. Since this type of product isrepresented by placing a cross between the vectors to the multiplied.

Chapter 3

MOTION


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39. motion: -when a body changes its position with respect to its surroundings it is said to

be in motion

40. Translatory (or linear motion) a body said to possess translatory motion when it movesalong a straight path.

41. Rotatory (or angular) motion: - when a body moves in a circle (i.e. may spin or rotate

about a fixed point). It is said to possess rotatory motion.

42. Oscillatory (or vibratory) motion: - when a body moves to and fro about a meanposition.

43. rest: - when a body does not change its position with respect to its surroundings it issaid to be at rest

44. kinematics: - It is the study of motion of objects without considering the forces acting

on them

45. Statics: - the study of objects at rest.46. Dynamics: - it is the study of cause of the motion.

47. Displacement: - it is the shortest straight line distance in a particular direction between

the two final and initial positions.48. Speed: - it is the distance covered per unit time OR the magnitude of velocity.

49. Velocity: - the rate of change of displacement is called velocity. OR the speed in aparticular direction50. rate :- anything divided by time

51. Uniform velocity: - the velocity which does not change in magnitude and direction OR

it is the equal distance covered by a body in equal intervals of time in a particular direction(however short the interval of time may be).

52. Acceleration: - the rate of change of velocity is called acceleration.

53. uniform acceleration: - when change in velocity is constant in equal intervals of time

54. Gravity: - it is the force by virtue of which the earth attracts the bodies towards itscentre.

55. Acceleration due gravity: -it is the acceleration produced in free falling bodies by

gravity.56. Newtons first law of motion: - according to it

a body continues its state of rest or uniform motion unless any external force

Acts on it57. Inertia: -it is the property of matter by virtue of which it opposes the change in its state

of rest or that of motion.

58. Force: - it is the agency that changes or tries to change the state of motion or that of rest

of the body.59. Newtons second law of motion: - according to it

When an unbalanced force acts on a body it produces acceleration in the body in

the direction of force such that the magnitude of acceleration is directly proportional to the

applied force and inversely proportional to mass.60. Newtons third law of motion: - according to it

Every action has an equal and opposite reaction

61. Weight: -weight of the body is the gravitational pull of the earth on the body.62. Tension: -when an object is suspended by a string, the force that acts along

the string and is equal in magnitude and opposite in direction to the weight is called tension.


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63. Contact force: -the force in the middle of the two pressed objects is called

contact force.

64. Thrust: -a forcefully pushing force.65. Up thrust: -it is a force that pushes things up in water.

66. Reaction: -the opposing force of action(application of force).

67. Friction: - the resistive or opposing force to the motion of the object

generated when the two surfaces are in contact.68. Static friction: - the friction between the body and the surface when the body

is at rest is called static friction.69. Kinetic or dynamic friction: -when the body is in motion relative to surface

then force of friction between object and surface is of kinetic or dynamic type.

70. sliding friction: -when a body slides on a surface the corresponding force of

friction between the object and the surface on which it slides is called sliding friction.71. rolling friction: -when the body rolls on a surface the corresponding force of

friction between the body and the surface on which it rolls is called rolling friction.

72. Limiting friction: - the maximum static friction where the object is on the

verge of slipping is called limiting friction.

73. Fluid friction: -when a solid body moves through a fluid (viscous medium),it experiences an opposing force on it called fluid friction.

74. Resistance: - the force that prevents the motion.

75. Frame of reference: -a set of coordinate axes in terms of which position or

movement may be specified or with reference to which physical phenomena may be statedmathematically.

76. Inertial frame of reference: -a frame of reference which is either at rest or

moves with constant velocity but the acceleration in it is zero and allows Newtons law tobe applicable in it.

77. Non inertial frame of reference: -such a frame of reference is accelerated.

78. Momentum: -momentum is defined as the product of mass and velocity ofthe body.

79. law of conservation of momentum: - the total momentum of an isolated

system before and after collision remains conserved80. Impulse: -the change in momentum that takes place when a large force acts

for a short interval of time.

81. Elastic collision: -the collision after which both the momentum and kinetic

energy are conserved.

82. Inelastic collision: -in such a collision momentum is conserved but thekinetic energy is altered.

Chapter 4

Motion in two dimensions


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definations with examples

83. Two dimensional motion: -if a body moves in two directions simultaneously

(along x and y axis or it moves in a plane) then its motion is called two dimensional. E.g

motion along circular path and projectile motion.84. Projectile: -any object that is given any initial velocity and whichsubsequently follows a path determined by the gravitational force acting on it and by the

frictional resistance of the atmosphere is called a projectile.

85. projectile motion: -if a body moves with a constant velocity along horizontaldirection and at the same time falls freely under the action of gravity( i.e. it has a constant

vertical acceleration g), then its motion is called projectile motion .e.g. motion of a shell

fired from gun, motion of a kicked football, jumping of a frog and locust, motion of shuttlecock in badminton.

86. Trajectory: -the path followed by a projectile under gravity is called

trajectory. It is parabola.

87. Point of projection (or launching): - it is the point from where a projectile isprojected into air under gravity.

88. Angle of projection (or elevation): - it is the angle made by a projectile with

horizontal plane.

89. Time of flight: -it is the total time taken by a projectile to remain in air i.ethe time elapsed between the launching and landing of a projectile.

90. Point of landing: -it is the point where a projectile strikes earth after going

through air under gravity.91. Maximum horizontal distance (H): -it is the maximum horizontal distance

covered by a projectile.

92. Horizontal range (R): - it is the distance covered by a projectile from thepoint of projection to the point of landing.

93. Maximum horizontal distance (or height): -the maximum height attained by

a projectile where its vertical component of velocity becomes zero.

94. Maximum range (R m). it is the maximum range attained by a projectile whenlaunched at an angle of 45o

95. Uniform circular motion: - when a body moves in circle with constant speed

it is said to be in uniform circular motion.

96. Angular displacement: - the angle subtended by a body in circular motion iscalled angular displacement. Its unit SI unit is radian.


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98. Radian: - the angular displacement is said to be one radian if length S of the arc is equal to

radius r of the circular path. Angular velocity: -the rate of change of angulardisplacement is called angular displacement.

99. Angular acceleration: -the rate of change of angular velocity is called angular

acceleration.

100. Tangential velocity: -the velocity directed tangent to the circle is called tangential or

linear velocity.

101. Tangential acceleration: -the acceleration produced when there is change in

magnitude of the velocity during circular motion.

102. Centripetal acceleration: -it is the acceleration directed towards the centre of the

rotating body and is generated when there is change in direction of the velocity.

103. Centripetal force: -the force responsible for centripetal acceleration acts along the

string or rope towards the centre

.

104. Time period of revolution: -the time required by a body to complete one revolution is

called its time period of revolution.

Chapter 5

Torque, Angular momentum and Equilibrium.(I am probably exaggerating a little, but I owe

my equilibrium to ink and paper)

105. Torque: - the turning effect of force is called torque OR the cross product of position

vector and the force applied.

106. Moment of a couple: -couple is a pair of forces with equal magnitude and opposite

direction, with lines of action that are parallel but don not coincide.

107. Centre of mass: -it is the point on object where the entire mass of the body is

concentrated.


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108. Centre of gravity: -it is the point where the net gravitational force acts. OR Thatpoint in a body or system around which its mass or weight is evenly distributed or

balanced and through which the gravity acts.

109. Equilibrium: -a body at rest or with uniform motion is said to be in equilibrium.

110. Static equilibrium: -when a body is at rest it is said to be in static equilibrium.

111. Dynamic equilibrium: -a body moving with uniform motion constitutes dynamic

equilibrium.

112. Translational equilibrium: -when a body moves constant linear velocity it results in

translational equilibrium.

113. Rotational equilibrium: -a type of equilibrium in which body rotates in a circle with

uniform angular velocity.

114. first condition of equilibrium: -according to it a body will be in equilibrium if thesum of all the forces acting on it is zero

115. second condition of equilibrium: - according to second condition of equilibrium thebody will be in equilibrium if the sum of all the torques acting on the system or body

is zero

116. Angular momentum: -angular momentum may be defined as the cross product ofposition vector and linear momentum. i.e. L = r p

Chapter 6

GRAVITATION(Gravitation is not responsible for people falling in love

Einstein)

117. Gravitation: - it is the natural force of attraction between the material bodies.

118. Gravitational field: - it is the around an object under which the effect of gravitation

con be experienced.

119. Newtons law of gravitation: it states that every body in the universe attracts every

other body in the universe with a force of attraction (gravitation) that is directly

proportional to the product of their masses and inversely proportional to the square

of the distance between them

120. Density: -mass per unit volume is called density.


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121. Weight: - it is a force through which the earth attracts the bodies towards its centre

is called weight of the body. W=mg

122. Weightlessness: -a condition of free fall OR it is a condition in which body does not

experience ( feel) the gravitational effect

.123. Artificial gravity: -a simulated gravity established in space by technological means

such as spinning of the satellite etc.

Chapter 7

WORK, POWER AND ENERGY

(The reason why worry kills more people than work isthat more people worry than work Robert frost)

124. Work: -work is said to be done on a body if it attains some displacement with the

application of force. OR it is the dot product of the applied force and the

displacement covered.

125. Conservative field: -A field is said to be conservative if work done is independent of

the

path followed and the net work done in a closed path is zero.

126. Power: -the rate of doing work is called power. OR work done per unit time.

127. Energy: -the ability or capacity to do work is called energy.

128. Kinetic energy: -the energy possessed by a body when it is in motion is called kinetic

energy

.

129. Potential energy: - the energy possessed by a body when it is at rest or hanged or dueits position is called potential energy.

130. law of conservation of energy: it states that the energy can neither be created nordestroyed

131. Wind: -the moving air is called wind.

132. Solar energy: -the energy of the sun light is called solar energy.

133. Fossils: - the remains of the organism of the past that owing to some devastations gotburied.


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Chapter 8

WAVE MOTION AND SOUND(The most beautiful sound in the world is your own heart

beat that gives you assurance that you will surviveeven when the people leave you in the lurch)

134. Vibrational motion: -when a body moves to and fro about its mean position it is said

to be in vibrational or oscillatory motion.

135. Periodic motion: -that motion that repeats by itself is called periodic motion.

136. Vibration: -one complete round trip of a body about its mean position is called

vibration.

137. Frequency: -the number of vibrations (or revolutions) per unit time is called

frequency.

138. Amplitude: -it is the maximum displacement of a vibrating body from the mean

position

.

139. simple harmonic motion: it is characterized by;

I. its motion is vibratoryII. acceleration of the body is directly proportional to the displacement about a fixed

point at the middle(mean position)

III. The motion of the body is always directed towards the mean position.

140. Simple pendulum: -a simple ideal pendulum consists of a point mass suspended withthe help of a weightless, inextensible and flexible string whose other end is attached

with the rigid body.

141. Time period: -time taken by a body to complete one vibration is called its time period

of vibration.

142. Natural time period: -the time period with witch a body vibrates in the absence of

external forces.

143. Natural frequency: -the frequency at which a system vibrates freely without beingdisturbed by an external force.

144. Seconds pendulum: -it is the pendulum whose time period is two seconds.


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145. Resonance: - when natural frequency of a body capable of vibrating matches with the

frequency of an external periodic force then the body starts vibrating with the

increased amplitudes. The phenomenon is called resonance.

146. Wave: - A wave is a traveling disturbance. OR a wave is a mechanism through witch

energy or disturbance travels from one place to the other.

147. Mechanical wave: - The wave that requires a material medium (solid, liquid or gas)

for its propagation is called mechanical wave.

148. Electromagnetic wave: - the waves that don not require material medium for their

propagation are called electromagnetic waves.

149. Transverse waves: - the waves whose vibrations are perpendicular to the direction of

the propagation of the waves.

150. Longitudinal or compressional waves: - a wave in witch vibrations are parallel to thedirection in which a wave is traveling, is called longitudinal (or compressional) wave.

151. Frequency of waves: -the number of waves passing through a point in one second iscalled frequency of waves.

152. Wave length: -it is the distance between two consecutive (side by side) crests or

troughs. But in case of longitudinal waves it is distance between two successive

compressions or rarefactions.

153. Sound: - sound is a form of energy that produces the sense of hearing. OR sound is aform of energy that produces sense of hearing in our auditory system.

154. Audible sound: -the sound that can be heard and it is of the frequency ranging

between 20 Hz to 20,000 Hz.

155. Infrasonic waves: -sound waves of frequency less than 20 Hz are called infrasonic

waves.

156. Ultrasonic waves: -The sound waves whose frequency is greater than 20,000 Hz are

called ultrasonic waves.

157. Music: -the sound that produces pleasant effect in our auditory system is called

music.

158. Noise: - the sound that has a random, jarring or disagreeable impact on our auditory

system.

159. Intensity of sound: -the amount of sound energy passing perpendicularly through the

unit area of a surface in one second is called intensity of the sound.


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160. Loudness: -the magnitude of sound produced in our auditory system is calledloudness OR the attribute of sound that determines the magnitude of the auditory

sensation produced and that primarily depends upon the amplitude of the sound

waves involved.

161. Weber-fechner law: according to it: the loudness of sound is directly proportional to

the log of intensity of the sound.

162. Intensity level: -the difference in the loudness of a given sound and the faintest sound

is called intensity level

.

163. Faintest sound: -the threshold sound before below it we can not hear.

164. Pitch of sound: -pith is that characteristics of sound with the help of witch a shrillsound can be distinguished from a grave one.

165. Quality: -quality of sound is characteristics of sound with helps distinguishing the

sound having same pitch and frequency.

166. Beats: - To strike repeatedly. OR The pulsation resulting from a combination of two

waves of slightly different frequency

167. Adiabatic process: - the thermodynamic process involving no loss or gain of energy in

the system or particular region.

168. Isothermal process: -the thermodynamic process during which the temperature of the

system remains constant is called isothermal process.

169. Dopplers effect: -the apparent change in pitch of the sound due to the relativemotion of the source and listener is called Dopplers effect.

170. Sonic boom: -an explosive sound caused by the shock waves preceding an aircraft

traveling at or above the speed of the sound.

171. principle of superposition of waves: - according to it: when particles of a medium are

disturbed simultaneously by two or more waves then their net displacement from

their mean position will be equal to the algebraic sum of the individual

displacements due to individual displacements

172. Standing or stationary waves: - standing wave also called stationary wave is thecombination of two waves moving in opposite direction, each with same amplitude

and energy and is generated when the string is confined at both the sides and then

vibrated.

173. Antinodes: -the points where the vibrating displacement is maximum from the

centre.


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174. Node: -the points of zero amplitude are called nodes.

175. fundamental frequency: - also called first harmonic is the lowest tone of harmonic

series

176. overtone: -if the string tuned properly such that two loops are formed then the

frequency f2with which now it vibrates first overtone or second harmonic

177. Sonometer: - standing waves generating device.

178. Loop: -the more or less circular figure that curves back to cross itself.

Chapte9

THE NATURE OF LIGHT

(An age is called DARK, not because the light fails toshine but because people refuse to see it. James

Michener.)

179. LIGHT: - THE NATURAL AGENT THAT STIMULATES SIGHT AND MAKESTHINGS VISIBLE.

180. Interference of waves: -if two exactly similar waves superpose each other (i.e. passthrough the same region of space simultaneously) then at some points they reinforce

(i.e. they help each other and their effect enhances) while at other points they cancel

each others effect (i.e. their net effect decreases. This phenomenon is known asinterference of light.

181. Phase coherence: -if the waves produced simultaneously are alike, they are said to be

in phase coherence.

182. Constructive interference: -constructive interference takes place when the waves

reinforce each other.

183. Destructive interference: - it is brought about when the waves cancel each others

effect.

184. Path difference: -it is the distance covered by waves measured from source to thegiven point.

185. Fringe spacing: -it is the distance between two consecutive bright or dark fringes.

186. Phase reversal: - when a wave traveling in a rare medium (medium of lower

refractive index) reflects from a denser medium of high refractive index, then its

crest before reflection becomes trough after reflection.


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187. Newtons rings: - if a beam of monochromatic light is allowed to fall on a Plano-

convex lens placed on a plane glass plate then alternate bright and dark rings are

produced. These rings are known as Newtons rings.

188. Diffraction:-the bending of light around the edges of an object. OR The breaking up

of a ray of light bands or into the colors of the spectrum, caused by the interferenceof one part of beam with another, as when the ray is deflected at the edge of an

opaque object or passes through a narrow slit.

189. Frensel diffraction: in Frensel diffraction the source and the screen are finite and thediffracted rays are not parallel.

190. Frawnhoffer diffraction: -in Frawnhoffer diffraction the point source of light and thescreen on witch the diffraction is to be produced are at infinite distance so that the

diffracted rays become parallel.

191. Diffraction grating: - a plate of glass or metal ruled with very close parallel lines,producing spectrum by interference or diffraction of light.

192. Grating element: -let a be the width of a slit and b be the width of an opaque then a +b is called grating element.

193. Path difference: -the difference in the optical paths of two light rays having commoninitial and final points. OR An X-ray beam is reflected from the

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first year physics by asadullah talpur

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