What is emf source? A source of electromotive force is a device in which non electrical energy is changed into electrical energy.Examples of e.m.f sources are electrical cells,thermocouples and generators. The e.m.f of the source is able to maintain its upper terminal positive and its lower terminal negative charge. When the switch is closed,the cell drives a clock wise current ...

What is the meaning of aberration? The defect in the image formed by a lens or mirror,revealed as a blurring and possibly a false coloration,these principal aberrations are spherical aberrations,coma,and astigmatism. Aberrations occur when light rays do not pass close to optic axis of the system but make a considerable angle to it such that it is no longer accurate ...

What is scalar and vector quantity? The quantities having magnitude and unit is called scalar quantity.Some of these quantities have direction also but vector laws are not applied. Some examples of vector quantities are: Electric charge Mass distance current Speed Power The quantities which have magnitude,unit and direction are called vector quantities.These quantities also follow triangle law of addition.Some examples ...

Comparison table :                   Astronomical telescope     Galilean telescope 1:In an astronomical telescope the eye piece is a convex lens. 1:In Galilean telescope the eye piece is concave lens. 2:It forms an inverted image. 2:It forms an erect image. 3:The length  of astronomical telescope is: L =f0   + fe   ...

Difference table between microscope and telescope:     Microscope      Telescope                                                                                                 ...

The polarity of an unlabelled magnet is determined by following methods. First method: Suspend the magnet freely with the help of a thread so that it can oscillate freely.When magnet comes to rest ,one end always points towards the northern end of the earth.This end of magnet is thus called the North pole.Similarly,the other end of the magnet pointing towards ...

Electromotive force: The emf is the energy supplied to unit charge by the cell or battery. It is also defined as “the potential difference between the terminals of a battery when no current is flowing through an external circuit when the circuit is open. Potential difference: The voltage across the terminals of the battery when the current is being drawn ...

Electrons are negatively charged particles.When placed in an electric field ,negatively charged plate will repel them while positively charged plate will attract them.So,the electrons will move from negatively charged plate to positively charged plate.Since positively charged plate is at higher potential,while negatively charged plate is at lower potential.Therefore electrons tend to go from region of lower potential to a region ...

Both electron volt and joule are the units of energy.Since energies at atomic level are very small and are expressed in electron volt rather than Joule because Joule is a bigger unit.Hence the unit electron volt for energy is more convenient than joule,when we are dealing with atoms and nuclei to express the energy.  

Idea of gas turbine is very old one,its working principle is an advanced version of wind mill.To achieve efficient working of turbine,the movement of  gas is controlled and directed to blades.The air which is under pressure supplied to turbine by air compressor. In gas turbine initially the air is obtained from atmosphere and compressed in air compressor.The air which is ...