Science [1 Marks Each] QUE - ANS

Our body is a good conductor of electricity.

Yes.
For example: Iron, copper etc.

Two separate wires are connected to the two terminals of the cell as shown below:

The current flows from one terminal to the other. When both wires are connected to same terminal, current will not flow.

In an electric circuit, the direction of current is taken to be from the positive terminal to the negative terminal of the electric cell.

When the terminals of the bulb are connected with that of electric cell by wires, a current pass through the filament of the bulb and it makes the bulb glow.

Graphite.

A cell produces electricity by chemical reactions taking place in it whereas battery is made up of two or more cells joined together.

Arrangement that provides a complete path for electricity to pass (current to flow) is known as electric circuit.

The two terminals: Negative and positive.

Electric cell is a source of energy. It produces a small amount of electricity from chemicals stored inside it.

Rubbers and plastic are used to cover electric wires and plug tops because they are insulators and do not allow electric current to pass when we touch plugs and switches.

Electric wires are made up of copper, aluminium.

Rubber and plastic.

We can stick the wires to the bulb at the two terminals by the tape or using solding machine as shown in the figure.

When a bulb is fused its filament breaks, which in turn breaks the electric circuit. Thus, current does not pass through it.

An electric cell has two terminals.
Explanation:
Two: An electric cell has two terminals, a negative terminal and a positive terminal (as shown in the given figure).

Insulator is the material that does not allow an electric current to pass through it. For example, wood, mica, asbestos, rubber, etc.

A screw driver is made of steel. It is a good conductor of electricity. So electricity can easily flow through it. Plastic is a bad conductor and does not allow electricity to pass through it. So, the electrician has a plastic handle to protect him from any shock.

Electric cell, wire and electric bulb.

When two or more cells are joined together, it is called a battery.

Because the switch is ON and therefore current will flow.

Materials that do not allow electric current to pass through them are called insulators.

Rubber.

Solution is as follow:

In torch, cells are connected in series.

We should never join the wires with two terminals of the electric cell. If we do so, the chemicals in the electric cell get used up very fast and the cell stops working.

If air were a good conductor of electricity, the electricity could scatter all around in atmosphere nearby the power stations. The men at work could die with electric shocks. The electricity could not be transmitted to homes, factories from power stations.

Materials that allow electric current to pass through them are called conductors.

An electric bulb may get fused due to break in its filament. A break in the filament of bulb means break in the path of current between the terminals of electric cell.

If we join two terminals of electric cell directly through a wire, the chemical in an electric cell get used up very fast and the cell will stop working.

If cells are connected in a series in a circuit, change of ends of any one of the cells will stop the flow of electricity and the bulb might not illuminate as circuit will not be completed.

True.
Explanation:
Metals are good conductors of electricity. They allow an electric current to flow through them easily. Hence, an electric current can flow through metals.

A filament is a thin wire fixed in the middle of a bulb connected to the two supporting wires.

Plastics is a bad conductor or insulator of electricity. It prevents us from electric shocks. To complete the circuit, we have to remove the plastic coating to connect wires so that the current may flow through the circuit.

Insulators such as plastic, rubber etc.

Copper and aluminium.

False.
Explanation:
Jute string is a bad conductor of electricity. If jute string is used to make an electric circuit, then the current will not flow through it. Hence, strings made of jute cannot be used to make circuits.

It is used in alarm clocks and wrist watches.

Advantages of dry cells are:

• They are light in weight and small in size.
• They can be transported from one place to another easily.
• There is no fear of leakage/spillage in dry cells.

An electric cell is a device that converts chemical energy into electrical energy. It has two metal plates indicating two terminals-negative and positive. It has chemical inside it.

The simple device that either breaks the circuit or completes it is called switch.

Never join the two terminals of the electric cell without connecting them through a switch and a device like a bulb: Because if you do so, the chemicals in the electric cell get used up very fast and the cell stops working.

We use electric cell in an alarm clock, wrist watch, transistor, camera, torch, etc.

Water is a good conductor of electricity and current passes very quickly through wet hands. Therefore, it can give us an electric shock.

Connecting wires, bulb, switch and cell are the essential components of an electric circuit.

Conductors and insulators are equally important for us. Switches, electrical plugs and sockets are made of conductors. On the other hand, rubber and plastic are used for covering the electrical wires, plug tops, switches and other parts of electrical appliances, which people might touch.