Students can go through AP State Board 7th Class Science Notes Chapter 7 Electricity – Current and Its Effect to understand and remember the concept easily.
AP State Board Syllabus 7th Class Science Notes Chapter 7 Electricity – Current and Its Effect
→ The dry cell converts chemical energy into electrical energy.
→ Symbols play an important role in our life.
→ Symbols convey precise meaning with few descriptions.
→ The switch can be placed anywhere in the circuit.
→ In a series circuit, electricity has only one path to flow through.
→ A parallel circuit has more than one path for the flow of electricity.
→ Connecting small cells in series, we get a battery.
→ In a series connection of bulbs, if one bulb gets fused, all the other bulbs in the series will stop glowing.
→ All components in our houses are connected in parallel.
→ The filament of the bulb heats up due to the current flowing through it.
→ An electric iron, electric cooker, and electric heater contain a coil of wire made up of Nichrome.
→ This Nichrome is called the filament of the appliance.
→ The wires used for making electric circuits do not normally become hot.
→ Wastage of electricity can be reduced by using fluorescent tube lights in place of bulbs. Miniature Circuit Breakers (MCB) are increasingly being used in place of fuses.
→ 1 kilowatt (KW) is 1000 watts (W).
→ An electric cell is a source of electric energy.
→The two terminals of an electric cell are called positive (+ve) and negative (-ve).
→ The battery cells in the torchlight are kept in series.
→ An electric bulb has a filament that is connected to its terminals.
→ An electric bulb glows when an electric current passes through it.
→ In a closed electric circuit, the electric current passes from one terminal of the electric cell to the other terminal.
→ The switch is a single device that is used either to break the electric circuit or to complete it.
→ The safety device used in, an electric circuit is a fuse.
→ Cell: A single unit for electrolysis or conversion of chemical into electric energy, usually consisting of a container with electrodes and an electrolyte; a battery also called electrochemical cell.
→ Battery: Two or more connected cells that produce a direct current by converting chemical energy to electrical energy.
→ Fuse: Safety device used in an electric circuit.
→ Serles circuit: An electric circuit connected so that current passes through each circuit element in turn without branching.
→ Parallel circuit: Circuits in which a power source is directly connected to two or more components are called parallel circuits.
→ Bulbs in series: A number of bulbs arranged or coming one after the other in succession.
→ Bulbs in parallel: A number of bulbs arranged directly.
→ Tube light: A lamp that produces visible light by fluorescence, especially a glass tube whose inner wall is coated with a material that fluoresces when an electrical current causes a vapor within the tube to discharge electrons.
→ Compact fluorescent Lamps: CFLs use less power and have a longer rated life,
→ Miniature Circuit Breaker: A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or a short circuit. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow.
Unlike a fuse.
→ Watt: An International System unit of power equal to one joule per second.
→ Circuit diagram: A schematic drawing of the wiring of an electrical system
→ Heating effect of current: Electrical energy converts into heat energy by a specialized device.
→ Switch: A device used to either break the circuit or to complete it.
→ Michael Faraday (1791-1867):
Michael Faraday observed that by moving a magnet in and out of a coil. We can make electric current flow thíough the coil. Using thiš he built the first electric generator or dynamo in 1831. He also invented the transformer.
→ Galileo: Galileo was an Italian scientist. He was born on 15th February 1564 in Italy. The first telescope of the world was fabricated by Galileo.
He proved that the milky way is composed of millions of stars.
In 1616, he proved for the first time that the sun was the center of the universe and the earth revolves around the sun. The church officials could riot tolerate Galileo‘s findings and sent him to jail. In the jail, the lie became blind arid died in January 1642.