WRITE THE ADVANTAGES AND DISADVANTAGES OF HEATING EFFECT OF ELECTRIC CURRENT.
Advantages :- many appliances can be designed like heater, geyser, rod etc.
Disadvantages :-unnecessary wastage of energy, because of this we have limited electricity otherwise we would have had infinite electricity, the devices made on this basis (like those mentioned above) are costly and are not energy efficient.
Ranveer felt that it was absurd to draw the diagrams of different components of an electrical circuit. His friend Kailash told him a convenient way of drawing these components. He suggested Ranveer to draw the symbolic representations of these components. Ranveer wanted to know what these symbolic representations of common components are.
An electric circuit consists of various electrical components such as a source, a device (a bulb), a switch, connecting wires, etc. The symbols of these components must be used to represent an electric circuit on paper. Hence, symbols play a very important role in the construction of electric circuits.
Description of Symbols
Its symbol has two parallel lines: one is longer than the other and they are separated by a small distance. Since electric cells have two terminals, the longer line represents the positive terminal, while the shorter one represents the negative terminal, as shown in the given figure.
Its symbol consists of a small section of spiral wire that is enclosed within a circle. Its two terminals are represented by two straight lines, as shown in the given figure.
Switch in ?OFF? position
A switch has a clip that can be attached to another terminal. If the clip is not attached to the terminal, then the switch is in the ?OFF? position, as shown in the given figure.
Switch in ?ON? position
If the clip has been attached to the other terminal, then it is in the ?ON? position as shown in the given figure.
Wires connect each component to make an electric circuit.
A battery is a combination of two or more cells connected in a line. Its symbol can be drawn by connecting the longer line of the symbol of one cell to the shorter line of the other cell, as shown in the given figure.
The above discussion on the symbolic representation of electric circuits can be summarized in a tabular form as
Many household devices such as radios, electric toys, remote controls, etc. use a combination of cells. However, some devices use batteries in which cells are placed side by side, as shown in the given figure.
A combination of four cells
Some more instruments and their symbols used in an electric circuit
Ammeter: It is an instrument used to measure electric current in an electric circuit. It is always connected in series with other electrical components so that the entire current passes through it. It is symbolically represented by letter A.
Galvanometer: This instrument detects very weak current in an electric circuit or is used to know the direction of flow of current in a circuit. It is connected in the same manner as an ammeter is connected in a circuit. It is symbolically represented by letter G.
Voltmeter: It is an instrument used to measure the potential difference between any two points in an electric circuit. It is always connected in parallel to the flow of current. It is symbolically represented by letter V.
Load: It is any another appliance connected in an electric circuit. It can be a resistance, a bulb,a heated etc. or a combination of electric appliances. Symbolically, it is represented by letter L.
Can you draw the symbolic representation of the battery used in a torch?
An unbroken path or line that makes electrical current flow possible through conducting wires connected to other resistances is known as an electric circuit. The figure below shows different components in an electrical circuit.
How do you construct an electric circuit?
You should follow some precautions while handling electric devices and circuits.
?Do not touch any device when it is connected to the mains
?Do not use the mains as the source of energy while constructing a simple circuit
?Do not use your teeth to peel the wires
Collect two bulbs, a switch, a battery that consist of two cells, and a piece of electric wire of sufficient length. Cut the wire in four pieces with the help of a wire cutter. Connect the two terminals of the battery with both bulbs using two pieces of wires. Connect the switch with the terminals of both bulbs using the two remaining pieces of wires.
[Note: You can refer to the given circuit diagram]
Keep the switch in the ?ON? position. Do both bulbs glow simultaneously? If the filament of one bulb is broken, then what will happen to the other bulb? Will the circuit become incomplete? Will the current still flow in the circuit? Is a circuit with a broken filament similar to the circuit in which the switch is in the ?OFF? position?
The circuit is complete in the ?ON? position. Hence, current passes through both the bulbs and they glow simultaneously. If the filament of one bulb is broken, then the circuit becomes incomplete and the other bulb does not glow. Therefore, this situation is similar to that of a circuit in which the switch is in the ?OFF? position.
Such circuits where the appliances in connection operates simultaneously once the switch is closed are known as series circuits. In series circuit, the working of each appliance is dependent on each other.
Now using two bulbs, two switch, battery that consist of two cells, and six pieces of electric wires of sufficient length, construct a circuit as shown in the figure.
The circuit will be complete for both the bulbs when both the switches are closed. Hence, current passes through both the bulbs and they glow simultaneously.
Now, if S1 is opened, the circuit for bulb B1 breaks whereas for B2, it still remains complete. Thus, current flows through bulb B2 and it glows. Similarly, the bulb B1 glows even if S 2 is opened.
Now, if the filament of one bulb is broken, then the circuit becomes incomplete for that bulb only and hence it stops glowing. But the circuit is still complete for the other bulb. Therefore, the current still flows through it keeping it in the glowing state.
Such circuits where the working of each appliance is independent of each other are known as parallel circuits.
Construct an electrical circuit consisting of a cell, a switch, and a bulb in such a way that the bulb does not glow.
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