Flashcards
Electrostatics (3 Mark Definitions)
Flashcards do conjunto (33)
- 1Applications of Attraction and Repulsiona) Electrostatic paint spraying
b) Powder coating
c) Fly-ash collection (chimneys)
d) Ink-jet printing
e) Photostat copying (Xerox) - 2Quantization of Electric ChargeElectric charge of any system is always an integral multiple of the least amount of charge. The quantity can take only one of a discrete set of values.
- 3Conservation of Electric ChargeElectric charge can neither be created nor destroyed. Total charge of an isolated system always remains constant, but charges can be transferred from one part of the system to another.
92 U 238 --> 90 Th 234 + 2 He 4 - 4Coulomb's LawThe force of attraction or repulsion between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The direction of the forces is along the line joining the two point charges.
- 5CoulombOne coulomb is defined as that quantity of charge, which, when placed at a distance of 1 m in air/vacuum from an equal and similar charge, experiences a repulsive force of 9 x 10^9 N.
- 6Electric Field IntensityElectric field intensity at a point in an electric field is defined as the force experienced by a unit positive charge kept at that point. It is a vector quantity. Its unit is N C^-1
- 7Electric Line of ForceAn imaginary straight or curved path along which a unit positive charge tends to move in an electric field.
- 8Electric DipoleTwo equal and opposite charges separated by a very small distance.
Ex: Water, ammonia, carbon dioxide, chloroform - 9Electric Dipole MomentThe dipole moment is given by the product of the charges and the distance between them.
Diploe moment, p = q2d (or) 2qd - 10Electric Potential EnergyElectric potential energy of an electric dipole in an electrostatic field is the work done in rotating the dipole to the desired position in the field.
- 11Microwave Oven (Principle)a) Microwaves produce a non-uniform oscillating electric field.
b) Water molecules are electric dipoles (excited by an oscillating torque)
c) Bond breakage releases energy used to cook food. - 12Potential DifferencePotential difference between two points in an electric field is defined as the amount of work done in moving a unit positive charge from one point to the other against the electric force.
- 13VoltThe unit of potential difference.
Potential difference between two points is 1 volt if 1 joule of work is done in moving 1 coulomb of charge from one point to another against the electric force. - 14Electric Potential at a PointThe amount of work done in moving a unit positive charge from infinity to that point against the electric forces.
- 15Electric Potential Energy (Two Point Charges)a) The work done to assemble two charges
b) The work done in bringing each charge
c) Work done in bringing a charge from infinite distance. - 16Equipotential SurfaceA surface on which all the points are at the same electric potential.
- 17Electric FluxThe total number of electric lines of force crossing through the given area. It is a scalar quantity. Its unit is N m^2 C^-1
- 18Gauss' LawTotal flux of the electric field over any closed surface is equal to 1/ε◦ times the net charge enclosed by the surface (Gaussian surface).
- 19Electrostatic ShieldingThe process of isolating a certain region of space from external field. It is based on the fact that the electric field inside a conductor is zero.
- 20Bus vs. Open GroundDuring thunder accompanied by lightning, it is safer to sit inside a bus than in open ground/under a tree. The metal body of the bus provides electrostatic shielding where the electric field is zero. During lightning, the electric discharge passes through the body of the bus.
- 21Electrostatic InductionIt is possible to obtain charges without any contact with another charge. They are known as induced charges and the phenomenon of producing induced charges is called electrostatic induction.
- 22CapacitorA charge storage device consisting of one or more pairs of conductors separated by an insulator.
- 23CapacitanceThe ratio of charge given to a conductor to the potential developed in it. Its unit is farad. A conductor has a capacitance of 1 farad if a charge of 1 coulomb given to it raises its potential by 1 volt.
- 24DielectricAn insulating material in which all the electrons are tightly bound to the nucleus. There are no free electrons to carry current. The electrons are not free to move under the influence of an external field.
- 25Non-Polar MoleculeA molecule in which the center of gravity of the positive charges (protons) coincides with the center of gravity of the negative charges (electrons).
Eg: Oxygen, nitrogen, hydrogen - 26Characteristics of Non-Polar Moleculesa) No permanent dipole moment
b) Centre of charges gets displaced in an electric field
c) Such molecules are polarized and are called induced dipoles.
d) They acquire dipole moment in the field direction. - 27Polar MoleculeA molecule in which the center of gravity of the positive charges is separated from the center of gravity of the negative charges by a finite distance.
Eg: Nitrous oxide, water, hydrochloric acid, ammonia - 28Characteristics of Polar Moleculesa) Permanent dipole moment.
b) Dipole moments orient the molecules in random directions in the absence of an external field (no net dipole moment).
c) Dipoles orient themselves in the direction of the electric field on its application. - 29PolarizationAlignment of dipole moments of polar molecules of the permanent/induced dipoles in the direction of the applied electric field.
- 30Applications of Capacitorsa) Ignition systems of automobile engines (elimination of sparking).
b) Voltage fluctuation reduction in power supplies (power transmission efficiency increased).
c) Generation of electromagnetic oscillations and radio circuit tuning. - 31Capacitors in SeriesThe reciprocal of the effective capacitance is equal to the sum of the reciprocals of the individual capacitances.
- 32Capacitors in ParallelThe effective capacitance is the sum of the capacitances of the individual capacitors.
- 33Corona Discharge / Action of PointsThe leakage of electric charges from the sharp points on the conductor.
Informações
- Descrição
- Higher School Certificate(HSC ) Physics (Electrostatics) FlashCards sobre Electrostatics (3 Mark Definitions), criado por Susanna Marian C em 25-12-2015.
- Criado por
- Susanna Marian C · dez 2015
- Atualizado
- 15 dez 2016
- Visualizações
- 103
- Tags
- Avaliação