EMF, Potential difference, Electrical power, Types of supply
  Electromotive force:-           Causes an electric current to flow in an electric circuit.       Potential difference:-                  Difference between electrical potential of two points which tends to cause flow of electrons between them.               Electrical potential of a point can be measured by the amount of work done in bringing a unit positive charge form infinity to that point.                Unit : volt (V).     Electrical power:-               Work done by the electrical instruments per a unit time.             P= W/t             Unit: Watt               Types of electrical power supply:-      1 .        DC Supply:                Polarity of the current/voltage/power of a source remains same with respect to...