Zener diode
A heavily doped p-n junction diode which work  in the break down region is called a zener diode.

Zener diode as a voltage regulator

A zener diode can be used as voltage regulator or voltage stabilizer to provide a constant voltage from a source whose voltage may fluctuate over a wide range.when the input voltage is increase resistance of zener diode decrease and hence the current through the diode increase to high value
As a result of this large voltage drop occurs across the dropping resistance R.hence the output voltage across RL is maintain to the desire value.when the input voltage decrease through the diode also now small voltage drop take place across the resistance R and the output voltage across RL is maintain at the desire constant value.


Eddy current

The induce circulating current produce in a conductor itself due to change in magnetic flux linked with the conductor is called eddy current.

Disadvantage of eddy current
1.the production of eddy current in a metallic block leads to the loss of electrical the form of heat.
2.the heat produce due to eddy current breaks the insulation used in the electrical machine.

The impedance of L.C.R circuit is define as the total effective a position offered by a circuit to flow of ac.

Electrical resonance
It is said to be take place in L.C.R circuit when the circuit is allow the maximum current for a given frequency of the alternative source for which the inductive resistance become equal to the capacitance resistance.

The solid having very low value of resistivity or very high value of conductivity are called as metal.

The solid having very high value of resistivity or low value of conductivity are called insulators.


Photons are the packets of energy which are emmited by a source of radiation.

Reading all those points will help you remember important points which
will help in easy and quick answer of the SSC general knowledge
questions or other competitive exam

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Electric energy
Work done by a source to maintain current in an electrical circuit is called an electric current.

Electric power
Electric power can be defined as rate of doing electrical work.

A cell is a electrical device which provides the necessary potential difference in an electrical circuit to maintain the flow of current.

Emf (electro motive force)
Emf of the may be defined as the potential difference between its terminal when no current is drawn from the cell.

Magnetic flux
Magnetic flux through any surface is define as a total number of magnetic field line passes through the surface.

Faraday law

1st law
Whenever there is a change in magnetic flux linked with a coil an emf induce in the coil this emf is as long as there is change in magnetic flux.

2nd law

The magnitude of induce emf is directly proportional to the rate of change of magnetic flux linked with a coil.


Ohm’s law
The current flowing through the conductor is directly proportional to the potential difference across its end provides the external condition like temperature,pressure remain constant.

The hindrance offered by the conductor in the flow of current is called as resistance.
S.I unit ohm.

Conductivity is defined as the inverse of resistivity.

Limitation of ohms law
1.change in nature of material occur with passage of current.
2.increase of current possible of decrease in voltage.
3.decrease of current is possible decrease in voltage.

Ohmic and non ohmic conductor
The conductor which obeys ohms law is called ohmic conductor.

The conductor which do not obeys the ohms law is called non ohmic conductor.


The non conducting material in which equal and opposite induce charges
are produce on their opposite face on the application of electric
field are called as dielectrics.
Ex.air,glass ,mica

Dielectric constant (k)
The ratio of the applied electric field to the reduce value of
electric field on placing the dielectric between the two oppositivly
charge plate is called dielectric constant.

A capacitor consist of two conducting bodies separated by a non
conducting medium such that it can store large amount of electric

Define one ampere?
Ans. A current is said to be one ampere if one coulomb of charge flow
through a cross sectional of any conductor in one second.

Drift velocity
Ans. drift velocity is defined as the average velocity with which free
electron in a conductor get drifted in a direction opposite to the
direction of applied electric field.

Relaxation time
The small interval of time between two success collision between
electron and ions in the conductor is called relaxation of time.

It is defined as the ratio of drift velocity to the applied electric field.

Current density
Current per unit area is called current density.


Homi Bhabha Centre for Science Education (TIFR), Mumbai, hereby invites applicants for Walk-in Interview

Vacancy-  · PROJECT ASSISTANT – 2 


Candidates with (i) B.Sc. /M.Sc., OR (ii) a professional Bachelor’s degree in engineering/technology with minimum 50 % or more marks at Graduate and Post Graduate levels.

He/She should have a good knowledge of Hindi language and be able to translate educational materials from English to Hindi.

should have computers knowledge preferably with Hindi software

For Project Assistant with Post Graduate degree (M.Sc.) or professional bachelor Degree    (B.E. /B.Tech.) – Rs. 10,000/- + 30% HRA in lieu of Government accommodation. · For Project Assistant with Bachelor’s degree (B.Sc.) – Rs. 7,500/- + 30% HRA in lieu of Government accommodation. Age:  Below 25 years ( five years relaxation to deserving cases).

Date & Time of Interview : Thursday, March 27, 2014 Time: 9:00 a.m. to 1:00 p.m.

Venue: Homi Bhabha Centre for Science Education, T.I.F.R

Important notes of geography

Bigbang theory is the theory about the explosion of the big massive lump known as primeral atom. The parts of it were formed as planets, galaxies.

Milkyway galaxy is our home galaxy that is the home of solar system and earth. It was formed 15 billion years ago.
Each galaxy has 10^11 stars.
There are total 10^22 stars in this universe.

Venus is the brightest planet and is said to be the earth’s twin in case of mass and earth size.

Venus is a veiled has clouds around it.and that’s why it is the hottest planet even more hotter than mercury.