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# Points to Remember

7th Science : Term 2 Unit 2 : Electricity : Points to Remember

POINTS TO REMEMBER

* An electric current is a flow of electric charge or the amount of charge flowing through a given cross section of a material in unit time.

* Conventional current is in the direction opposite to electron flow.

* One ampere is defined as the flow of electric charge across a surface at the rate of one coulomb per second.

* An electric cell is something that provides electricity to different devices that are not fed directly or easily by the supply of electricity

* A dry cell is a portable form of a leclanche cell

* Batteries are a collection of one or more cells whose chemical reactions create a flow of electrons in a circuit

* The cell is the basic single electrochemical unit which converts chemical energy to electrical energy.

* Ammeter — An instrument for measuring the flow of electrical current in amperes. Ammeters are always connected in series with the circuit to be tested.

* Ampere (A) — A unit of measure for the intensity of an electric current flowing in a circuit. One ampere is equal to a current flow of one coulomb per second.

* Circuit — A closed path in which electrons from a voltage or current source flow. Circuits can be in series, parallel, or in any combination of the two.

* Current (I) — The flow of an electric charge through a conductor. An electric current can be compared to the flow of water in a pipe. Measured in ampere.

* Fuse — A circuit interrupting device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a safe level.

* Conductor — Any material where electric current can flow freely. Conductive materials, such as metals, have a relatively low resistance. Copper and aluminum wire are the most common conductors

* Insulator — Any material where electric current does not flow freely. Insulation materials, such as glass, rubber, air, and many plastics have a relatively high resistance. Insulators protect equipment and life from electric shock.

* Parallel Circuit — A circuit in which there are multiple paths for electricity to flow. Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents.

* Series Circuit — A circuit in which there is only one path for electricity to flow. All of the current in the circuit must flow through all of the loads.

*  Short Circuit — When one part of an electric circuit comes in contact with another part of the same circuit, diverting the flow of current from its desired path.

* One unit of coulomb is charge of approximately 6.242×1018 protons or electrons.

* The potential difference between any two points is the amount of energy needed to move one unit of electric charge from one point to the other.

* Electrical conductivity or specific conductance is the measures a material’s ability to conduct an electric current

* Electrical resistivity is the property of a material that quantifies how strongly that material opposes the flow of electric current.

* The sources which produce the small amount of electricity for shorter periods of time is called as electric cell or electro chemical cells.

*Electrolytes: A substance that dissociates into ions in solution and acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, and phosphate are examples of electrolytes.

ICT CORNER

ELECTRICITY

This activity helps the students to understand about the Parrellel and series circuit

PROCEDURE:

Step 1: Type the URL link given below in the browser or scan the QR code. A page opens with a battery , some cables, two sets for circuit and two bulbs.

Step 2: Ask the students to fix the wires to the battery and the circuit

Step 3: Let the students do it and understand the concept with different combinations

Electricity URL:

http://www.physics-chemistry-interactive-flash-animation.com/electricity_ electromagnetism_interactive/components_circuits_association-series_parallel.htm

*Pictures are indicative only

*If browser requires, allow Flash Player or Java Script to load the page.

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7th Science : Term 2 Unit 2 : Electricity : Points to Remember | Electricity | Term 2 Unit 2 | 7th Science