what is current?give explanation
Answers
Answer:
Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms. ... Physicists consider current to flow from relatively positive points to relatively negative points; this is called conventional current or Franklin current. Electrons, the most common charge carriers, are negatively charged.Current in simple words is Flow in a definite direction. Here in electrical field , Current means there is flow of charges . If we go more close to it mathematically , we come to know , current is the rate of flow of charge or we say charge flow per unit time . I = Q / t (amp) .
Explanation:
current is movement of charge, usually, but not strictly, from one place to another*. Some examples of current:
Electrons flowing in a conductor, semiconductor or even a vacuum (think about a cathode ray tube)
Positrons and electrons and even charged atoms (ions) flowing in a particle accelerator.
Electrons and ions flowing out from the sun, although the net flow of current out of the sun (carried by the ions) pretty much balances the current flow into the sun (carried by the electrons)
Electrons and holes (a type of positive charge) in a semiconductor LED or solar cell
Ions flowing in a fluid (think about a lead-acid battery or electroplating operation)
Shuffling your feet on a carpet on a low-humidity day and carrying a static-charge build up with you across the room.
Shocking your little brother with that static-charge buildup (think of lightning)
It's true that those electrons (and holes too) are bound to their atoms. However, all it takes is a little bit of extra energy to free them up so that they can move around. That energy can come from a variety of sources, including
Mechanical energy - as in rubbing your feet on the carpet
Electrical energy - a little bit of voltage
Electromagnetic energy - light (photovoltaic and photoelectric effects)
Heat energy - the emitter of a vacuum tube or cathode ray tube
Nuclear energy - alpha particles from tritium decay bouncing through a semiconductor material (for example)
In conductors, not so much energy is needed to free up those electrons, in fact, there's a good number that are free at room temperature (so, current flows easily). In insulators, a whole lot of energy is needed to free them up, and there are basically none free at room temperature (so, no current flows). In semiconductors, well, it's somewhere in between for the most part (so current flows when and where we want it to flow).