common formula p , i , v ,r

kinetic energy

motion

Force

From Wikipedia, the free encyclopedia

For other uses, see Force (disambiguation) and Forcing (disambiguation).

Force
Forces are also described as a push or pull on an object. They can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate.
Common symbols	F, F
SI unit	newton
In SI base units	1 kg·m/s2
Derivations from other quantities	F = m a

In physics, a force is any interaction which tends to change the motion of an object.^[1] In other words, a force can cause an object with mass to change itsvelocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described by intuitive concepts such as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.

The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object. As a formula, this is expressed as:

where the arrows imply a vector quantity possessing both magnitude and direction.

Related concepts to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque which produces changes in rotational speed of an object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the so-called mechanical stress. Pressure is a simple type of stress. Stress usually causes deformation of solid materials, or flow in fluids.

physics greater scientist Galileo Galilei

Galileo Galilei

From Wikipedia, the free encyclopedia

"Galileo" redirects here. For other uses of "Galileo", see Galileo (disambiguation). For other uses of "Galileo Galilei", see Galileo Galilei (disambiguation).

Galileo Galilei
Portrait of Galileo Galilei by Giusto Sustermans
Born	15 February 1564 Pisa, Duchy of Florence, Italy
Died	8 January 1642 (aged 77) Arcetri, Grand Duchy of Tuscany, Italy
Residence	Grand Duchy of Tuscany, Italy
Nationality	Italian
Fields	Astronomy, physics, natural philosophy and mathematics
Institutions	University of Pisa University of Padua
Patrons	Cardinal del Monte Fra Paolo Sarpi Prince Federico Cesi Cosimo II de Medici Ferdinando II de Medici Maffeo Barberini
Alma mater	University of Pisa
Academic advisors	Ostilio Ricci[1]
Notable students	Benedetto Castelli Mario Guiducci Vincenzo Viviani[2]
Known for	Kinematics Dynamics Telescopic observational astronomy Heliocentrism
Signature
Notes His father was the musician Vincenzo Galilei. Galileo Galilei's mistress Marina Gamba (1570 – 21 August 1612?) bore him two daughters (Maria Celeste (Virginia, 1600–1634) and Livia (1601–1659), both of whom became nuns) and a son Vincenzo (1606–1649), a lutenist.

Galileo Galilei (Italian pronunciation: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564^[3] – 8 January 1642), often known mononymously as Galileo, was an Italian physicist, mathematician, engineer, astronomer, and philosopher who played a major role in the scientific revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy",^[4] the "father of modern physics",^[5][6] the "father of science",^[6][7] and "the Father of Modern Science".^[8]
His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.
Galileo's championing of heliocentrism was controversial within his lifetime, a time when most subscribed to either geocentrism or the Tychonic system.^[9] He met with opposition from astronomers, who doubted heliocentrism due to the absence of an observed stellar parallax.^[9] The matter was investigated by the Roman Inquisition in 1615, which concluded that heliocentrism was false and contrary to scripture, placing works advocating the Copernican system on the index of banned books and forbidding Galileo from advocating heliocentrism.^[9][10] Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII, thus alienating not only the Pope but also the Jesuits, both of whom had supported Galileo up until this point.^[9] He was tried by the Holy Office, then found "vehemently suspect of heresy", was forced to recant, and spent the rest of his life under house arrest.^[11][12] It was while Galileo was under house arrest that he wrote one of his finest works, Two New Sciences, in which he summarised the work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials.^[13][14]

semi conductor

radio wave

type of state

plasma

Current density and Ohm's law

Current density and Ohm's law

Main article: Current density

Current density is a measure of the density of an electric current. It is defined as a vector whose magnitude is the electric current per cross-sectional area. In SI units, the current density is measured in amperes per square metre.

where is current in the conductor, is the current density, and is the differential cross-sectional area vector.
The current density (current per unit area) in materials with finite resistance is directly proportional to the electric field in the medium. The proportionality constant is called the conductivity of the material, whose value depends on the material concerned and, in general, is dependent on the temperature of the material:

The reciprocal of the conductivity of the material is called the resistivity of the material and the above equation, when written in terms of resistivity becomes:

or

Conduction in semiconductor devices may occur by a combination of drift and diffusion, which is proportional to diffusion constant and charge density . The current density is then:

with being the elementary charge and the electron density. The carriers move in the direction of decreasing concentration, so for electrons a positive current results for a positive density gradient. If the carriers are holes, replace electron density by the negative of the hole density .
In linear anisotropic materials, σ, ρ and D are tensors.
In linear materials such as metals, and under low frequencies, the current density across the conductor surface is uniform. In such conditions, Ohm's law states that the current is directly proportional to the potential difference between two ends (across) of that metal (ideal) resistor (or other ohmic device):

where is the current, measured in amperes; is the potential difference, measured in volts; and is the resistance, measured in ohms. For alternating currents, especially at higher frequencies, skin effect causes the current to spread unevenly across the conductor cross-section, with higher density near the surface, thus increasing the apparent resistance.

GASES AND PLASMAS

Gases and plasmas

In air and other ordinary gases below the breakdown field, the dominant source of electrical conduction is via relatively few mobile ions produced by radioactive gases, ultraviolet light, or cosmic rays. Since the electrical conductivity is low, gases are dielectrics or insulators. However, once the applied electric field approaches the breakdown value, free electrons become sufficiently accelerated by the electric field to create additional free electrons by colliding, and ionizing, neutral gas atoms or molecules in a process called avalanche breakdown. The breakdown process forms a plasma that contains enough mobile electrons and positive ions to make it an electrical conductor. In the process, it forms a light emitting conductive path, such as a spark, arc or lightning.
Plasma is the state of matter where some of the electrons in a gas are stripped or "ionized" from their molecules or atoms. A plasma can be formed by high temperature, or by application of a high electric or alternating magnetic field as noted above. Due to their lower mass, the electrons in a plasma accelerate more quickly in response to an electric field than the heavier positive ions, and hence carry the bulk of the current. The free ions recombine to create new chemical compounds (for example, breaking atmospheric oxygen into single oxygen [O₂ → 2O], which then recombine creating ozone [O₃]).^[17]

RADIO WAVES

Main article: Radio waves

When an electric current flows in a suitably shaped conductor at radio frequencies radio waves can be generated. These travel at the speed of light and can cause electric currents in distant conductors.

Conduction mechanisms in various media

Main article: Electrical conductivity

In metallic solids, electric charge flows by means of electrons, from lower to higher electrical potential. In other media, any stream of charged objects (ions, for example) may constitute an electric current. To provide a definition of current that is independent of the type of charge carriers flowing, conventional current is defined to be in the same direction as positive charges. So in metals where the charge carriers (electrons) are negative, conventional current is in the opposite direction as the electrons. In conductors where the charge carriers are positive, conventional current is in the same direction as the charge carriers.
In a vacuum, a beam of ions or electrons may be formed. In other conductive materials, the electric current is due to the flow of both positively and negatively charged particles at the same time. In still others, the current is entirely due to positive charge flow. For example, the electric currents in electrolytes are flows of positively and negatively charged ions. In a common lead-acid electrochemical cell, electric currents are composed of positive hydrogen ions (protons) flowing in one direction, and negative sulfate ions flowing in the other. Electric currents in sparks or plasma are flows of electrons as well as positive and negative ions. In ice and in certain solid electrolytes, the electric current is entirely composed of flowing ions.

electro meganet

Main article: Electromagnet

According to Ampère's law, an electric current produces a magnetic field.

Electric current produces a magnetic field. The magnetic field can be visualized as a pattern of circular field lines surrounding the wire that persists as long as there is current.
Magnetism can also produce electric currents. When a changing magnetic field is applied to a conductor, an Electromotive force (EMF) is produced, and when there is a suitable path, this causes current.
Electric current can be directly measured with a galvanometer, but this method involves breaking the electrical circuit, which is sometimes inconvenient. Current can also be measured without breaking the circuit by detecting the magnetic field associated with the current. Devices used for this include, current clamps, Hall effect sensors current transformers, and Rogowski coils.

semiconducter

 Semiconductor

In a semiconductor it is sometimes useful to think of the current as due to the flow of positive "holes" (the mobile positive charge carriers that are places where the semiconductor crystal is missing a valence electron). This is the case in a p-type semiconductor. A semiconductor has electrical conductivity intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 10⁻² to 10⁴ siemens per centimeter (S⋅cm⁻¹).
In the classic crystalline semiconductors, electrons can have energies only within certain bands (i.e. ranges of levels of energy). Energetically, these bands are located between the energy of the ground state, the state in which electrons are tightly bound to the atomic nuclei of the material, and the free electron energy, the latter describing the energy required for an electron to escape entirely from the material. The energy bands each correspond to a large number of discrete quantum states of the electrons, and most of the states with low energy (closer to the nucleus) are occupied, up to a particular band called the valence band. Semiconductors and insulators are distinguished from metals because the valence band in any given metal is nearly filled with electrons under usual operating conditions, while very few (semiconductor) or virtually none (insulator) of them are available in the conduction band, the band immediately above the valence band.
The ease with which electrons in the semiconductor can be excited from the valence band to the conduction band depends on the band gap between the bands. The size of this energy bandgap serves as an arbitrary dividing line (roughly 4 eV) between semiconductors and insulators.
With covalent bonds, an electron moves by hopping to a neighboring bond. The Pauli exclusion principle requires the electron to be lifted into the higher anti-bonding state of that bond. For delocalized states, for example in one dimension – that is in a nanowire, for every energy there is a state with electrons flowing in one direction and another state with the electrons flowing in the other. For a net current to flow, more states for one direction than for the other direction must be occupied. For this to occur, energy is required, as in the semiconductor the next higher states lie above the band gap. Often this is stated as: full bands do not contribute to the electrical conductivity. However, as the temperature of a semiconductor rises above absolute zero, there is more energy in the semiconductor to spend on lattice vibration and on exciting electrons into the conduction band. The current-carrying electrons in the conduction band are known as "free electrons", although they are often simply called "electrons" if context allows this usage to be clear.

ELETRIC CURRENT

An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in a plasma.^[1]
The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter.^[2]
Electric currents can have many effects, notably heating, but they also create magnetic fields, which a.

transverse wave

shock wave figer

frequency graph

wave graph

wave properties

wave figer

Polarization (waves)

Main article: Polarization (waves)

A wave is polarized if it oscillates in one direction or plane. A wave can be polarized by the use of a polarizing filter. The polarization of a transverse wave describes the direction of oscillation in the plane perpendicular to the direction of travel.
Longitudinal waves such as sound waves do not exhibit polarization. For these waves the direction of oscillation is along the direction of travel.

Seismic waves

Seismic waves are waves of energy that travel through the Earth's layers, and are a result of an earthquake, explosion, or a volcano that imparts low-frequency acoustic energy. Many other natural and anthropogenic sources create low amplitude waves commonly referred to as ambient vibrations. Seismic waves are studied by geophysicists called seismologists. Seismic wave fields are recorded by a seismometer, hydrophone (in water), or accelerometer.
The propagation velocity of the waves depends on density and elasticity of the medium. Velocity tends to increase with depth, and ranges from approximately 2 to 8 km/s in the Earth's crust up to 13 km/s in the deep mantle.^[1]
Earthquakes create various types of waves with different velocities; when reaching seismic observatories, their different travel time help scientists to locate the source of the earthquake hypocenter. In geophysics the refraction or reflection of seismic waves is used for research into the structure of the Earth's interior, and man made vibrations are often generated to investigate shallow, subsurface structures.

water wave

Main article: Water waves

• Ripples on the surface of a pond are actually a combination of transverse and longitudinal waves; therefore, the points on the surface follow orbital paths.
• Sound—a mechanical wave that propagates through gases, liquids, solids and plasmas;
• Inertial waves, which occur in rotating fluids and are restored by the Coriolis effect;
• Ocean surface waves, which are perturbations that propagate through wat

wave

From Wikipedia, the free encyclopedia

This article is about waves in the scientific sense. For waves on the surface of the ocean or lakes, see Wind wave. For other uses of wave or waves, see Wave (disambiguation).

Surface waves in water

In physics, a wave is disturbance or oscillation that travels through matter or space, accompanied by a transfer of energy. Wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass transport. They consist, instead, of oscillations or vibrations around almost fixed locations. Waves are described by a wave equation which sets out how the disturbance proceeds over time. The mathematical form of this equation varies depending on the type of wave.
There are two main types of waves. Mechanical waves propagate through a medium, and the substance of this medium is deformed. The deformation reverses itself owing to restoring forces resulting from its deformation. For example, sound waves propagate via air molecules colliding with their neighbors. When air molecules collide, they also bounce away from each other (a restoring force). This keeps the molecules from continuing to travel in the direction of the wave.
The second main type of wave, electromagnetic waves, do not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic fields generated by charged particles, and can therefore travel through a vacuum. These types of waves vary in wavelength, and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.
Further, the behavior of particles in quantum mechanics are described by waves. In addition, gravitational waves also travel through space, which are a result of a vibration or movement in gravitational fields.
A wave can be transverse or longitudinal depending on the direction of its oscillation. Transverse waves occur when a disturbance creates oscillations perpendicular (at right angles) to the propagation (the direction of energy transfer). Longitudinal waves occur when the oscillations are parallel to the direction of propagation. While mechanical waves can be both transverse and longitudinal, all electromagnetic waves are transverse

physics equation

Balloon Rocket Car project

Balloon Rocket Car

Purpose

To demonstrate Newton's Third Law of Motion by constructing a balloon-powered rocket car.

---

Additional information

Newton's Third Law of Motion (law of reciprocal actions) states: "Whenever a particle A exerts a force on another particle B, B simultaneously exerts a force on A with the same magnitude in the opposite direction. The strong form of the law further postulates that these two forces act along the same line." This law is often summed up in the very cliché saying "Every action has an equal and opposite reaction".

GUJARAT UNIVERSITY Syllabus for First Year B. Sc.: Semester - I PHYSICS

GUJARAT UNIVERSITY

Syllabus for First Year B. Sc.: Semester - I

PHYSICS : PHY-101

Unit – I : Vector Analysis:

Introduction, Applications of V

ector Multiplication, Triple Scal

ar Product, Triple Vector

Product, Differentiation of Vect

ors, Fields, Directional Derivative, Gradient, Some other

expressions involving

∇

, Green’s Theorem in the plane, The Divergence and the Divergence

theorem. Gauss’s law, The curl and Stoke’s theorem.

Reference Book :

Mathematical Methods in Physical Sciences

by M. L. Boas (John Wiley & Sons) Chapter 6

Introduction to Classical Mechanics by R. G.

Takwalw and P. S. Puranik (Tata McGraw-Hill

Pub. Com. Ltd.) Chapters 1,2.

UNIT – II : Waves:

Traveling Waves

Speed of propagation of waves in a stretched stri

ng longitudinal waves in a bar, Plane waves

in a fluid, transmission of energy by a traveling wave.

Sound waves

Introduction, Intensity & intensity level,

Loudness & pitch radiation from a piston,

diffraction, radiation effici

ency of a sound source.

Newton’s and Langrang correction.

Ultrsonics

Magneostriction method,Piezo-elect

ric oscillator, Piezo-electric detectors, Measurement of

velocity of ultrasonic waves, diffraction effect

& its application to determine the velocity of

the waves, the ultrasonic waves & its use.

Reference Book :

Mechanics, Wave motion & Heat by Francis

Weston Sears (Addision Wesley Publication)

Articles : 16.3 to 16.6, 18.1, 18.2, 18.3, 18.6, 18.7

A text book on oscillations, wave

s & Acoustics by M. Ghosh, D. Bhattacharya (S. Chand)

Chapter 23 : Art 23.1 to 23.6

Unit – III : Optics:

Farmat’s principle and its applications:

Farmat’s principle of least time, laws

at reflection, laws of refraction.

Interference in thin films:

Thin film, Plane parallel film, Interference due to transmitted light, Haidinger fringes,

variable thickness (wedge-s

haped) film, Newton’s ring.

Matrices:

Types of matrices, Inversion of a Matrix, Rank

of a Matrix, Diagonalization (3X3 only) .

Matrix Method in Optics :

Introduction, The matrix method, Unit planes, No

dal point planes, A system of two thin

lenses.

Reference Book :

A text book of Optics by N. Subrahmanyam,

Brijlal and M. N. Avadhnulu, S. Chand

Publication: Articles : 2.2, 2.5, 2.6, 15.1

to 15.6 (including all sub articles)

Optics – Ajay Ghatak, TMH Edition, Articles : 3.1 to 3.5

Principle of optics – B. K. Mathur

Unit – IV : LASERS

Introduction, Attenuation of light

in an optical medium, Thermal equilibrium, Interaction of

light with matter, Einstein coefficients and

their relations, Light amplification, Meeting the

three requirements, Components of Laser, La

sing action, Principal pumping schemes, Type

of lasers, Semiconductor laser, Laser

beam characteristics, Applications

Reference Books:

A text book of Optics by N. Subrahmanyam,

Brijlal and M. N. Avadhnulu, S. Chand

Publication: Chapter 22 (i

ncluding all sub articles)

Fiber Optics and optoelectronics by R.

P. Khare, Oxford University Press.

An introduction to LASERS- Theory and Appl

ications by M. N. Avadhanulu, S. Chand &

Comp. Ltd.,

Page 3 of 6

GUJARAT UNIVERSITY

Syllabus for First Year

B. Sc.: Semester - I

PHYSICS Practicals : PHY-102

1. Newton’s Ring

To find the wave length of light of given monochromatic source

To find the radius of curvature of given lens.

2. Cauchy’s Constant

To determine Cauchy’s constant A and

B using given formula and to find the

wavelength of unknown line of a mercur

y spectrum. To determine Cauchy’s

constant A and B graphically and to

find the wavelength of unknown line of a

mercury spectrum.

3. Melde’s Experiment.

(i) To prove P/L consta

nt. (ii) To prove T/l

2

constant

4. Resonator

To test the accuracy of relation n

2

(V + Kv) = constant and to determine the frequency

of unknown fork.

5. Optical Lever

To determine the flatness and refractive inde

x of glass plate and ra

dius of curvature of

lenses by optical lever.

6. To Determine Wave length of LASER light

7.

Diagonalization of given matrix (2x2)

. Evaluate trace of a matrix.

Remuneration to the Deputy Coordinator

8. Value of capacitance

For given two capacitors determine the valu

e of capacitance for each of them. AND

(i) by connecting them in seri

es. (ii) by connecting them parallel.

9. Value of inductance

For given two inductors determine the value of

inductance for each of them and (i) by

connecting them in series (i

i) by connecting them parallel.

10.

Study of Transformer

To determine (i) turn ratio (ii) percentage

efficiency (iii) energy loss due to copper,

for a given transformer.

11. Decay Constant

To verify the exponential law for the decay of a charged capacitor and determine the

decay constant of the capacitor.

12. Logic Gates (AND, OR, NOT)

(Using discrete components)

Verification of truth tables and giving

understanding of voltage level for ‘0’and

‘1’level.

13.

Half-Wave Rectifier

Obtain load characteristic and %regulati

on for Full-wave rectifier with-out filter

circuit and by using capacitor filter circuit. Determine ripple factor for Full wave

rectifier without filter only.

14. Series Resonance

To determine the frequency of a.c. emf by se

ries resonance circu

it varying capacitor.