std 8 Electric current
11 ELECTRIC CUrrent points to remember : 1. Electric current : A flow of electric charges is called an electric current. 2. Conversion of electrical energy into light : When the positive and negative ends (or poles) of a dry cell (an electrochemical cell) are connected to an electric bulb with copper wires, the cell moves the negative stationary charges in the wires by applying a force on them. The resulting electric current passes through the filament of the bulb. The resulting rise in the temperature of the filament makes it glow. Thus, electrical energy is converted into light. 3. Electromotive force : The force applied by an electrochemical cell on electric charges is called the electromotive force. It sets electrons in motion. 4. Types of electrochemical cell : The simple cell, Leclanche cell, dry cell, nickel-cadmium cell, button cell (lithium cell) are various types of electrochemical cell. 5. Magnetic field of an electric current : A curren...