Important Questions Test: Electricity & Circuits - Class 6 MCQ

Only a closed circuit is a complete circuit.

The current flow through the circuit and the bulb glows in the closed circuit

Metal cap is the positive terminal of the electric cell. The Metal disc is the negative terminal.

An incandescent light bulb has a small thin wire with two bigger wires holding it up. This wire is called a filament. The filament is the part of the light bulb that produces light. Filaments in incandescent light bulbs are made of tungsten.

A combination of two or more electric cells is called a battery. This assembly is important because it:

• Provides a higher voltage when connected together.
• Delivers a greater current to power devices.

Electric Bulb Terminals:
- An electric bulb typically has two terminals.
- These terminals are used to connect the bulb to an electrical circuit.
- One terminal is the positive (+) terminal, also known as the anode.
- The other terminal is the negative (-) terminal, also known as the cathode.
- The positive terminal is connected to the live wire or the positive side of the power source.
- The negative terminal is connected to the neutral wire or the negative side of the power source.
- When the bulb is properly connected to a circuit, the flow of electric current passes through the terminals and causes the bulb to light up.
- It is important to correctly identify and connect the terminals to ensure proper functioning of the bulb and avoid any electrical hazards.
- The terminals of an electric bulb are usually made of metal and are designed to securely hold the wires in place for a stable connection.

The electric device that easily closes or opens an electric circuit is an electric switch.

Explanation:
- Electric switch: An electric switch is a device that is used to control the flow of electricity in a circuit. It can easily open or close an electric circuit by interrupting or allowing the flow of current.
- Filament: A filament is a wire or thread that is heated to produce light in an electric bulb. It is not responsible for opening or closing an electric circuit.
- Electric bulb: An electric bulb is a device that produces light when an electric current passes through its filament. It is not designed to open or close an electric circuit.
- Electric cell: An electric cell is a device that converts chemical energy into electrical energy. It is not used to open or close an electric circuit.
Therefore, the correct answer is Electric switch (C) as it is specifically designed to easily open or close an electric circuit.

An electrical insulator is a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field. 

Carbon is the only gas, when solidified, that can conduct electricity. This is of the form Graphite, when it only has 3 bonds between the atoms. This leaves electrons to flow through the network structure.

Conductors are the materials or substances which allow electricity to flow through them. They are able to conduct electricity because they allow electrons to flow inside them very easily.

In simple cell battery converts chemical energy into electricity. The chemical reaction produces electrons, which then collect at the negative terminal of the battery. When there is a connection between the positive and negative terminal, the electrons flow to the positive terminal.

Closed circuit means a complete electrical connection around which current flows or circulates.

The insulator among the given options is Rubber. Here is a detailed explanation:
Metal:
- Metals are good conductors of electricity and heat.
- They have a high density of free electrons that can move easily through the material, allowing the flow of electrical current.
- Therefore, metals are not insulators.
Acid:
- Acids are electrolytes that can conduct electricity when dissolved in water.
- They contain ions that can move and carry electrical charge.
- Therefore, acids are not insulators.
Rubber:
- Rubber is a good insulator of electricity and heat.
- It has high resistance to the flow of electrical current.
- Rubber is commonly used in electrical insulation, such as in cables and wires, to prevent the risk of electric shock.
- Therefore, rubber is an insulator.
Salt solution:
- Salt solutions are electrolytes that can conduct electricity.
- When dissolved in water, salts dissociate into ions that can carry electrical charge.
- Therefore, salt solutions are not insulators.
In conclusion, among the given options, rubber is the insulator. It has high resistance to the flow of electrical current, making it suitable for electrical insulation purposes.

Conductor:
- A conductor is a material that allows the flow of electric current through it.
- It is characterized by its ability to conduct heat and electricity.
- Conductors have high electrical conductivity.
- They have free electrons that can move easily through the material.
- The flow of electrons constitutes an electric current.
- Conductors are used in various electrical and electronic devices to carry and transmit electricity.
- Examples of common conductors include metals such as copper, aluminum, and silver.
- These metals have high electrical conductivity due to the presence of loosely bound electrons.
- Among the given options, metal (option B) is the only material that is a conductor.
- Wood (option A), paper (option C), and petrol (option D) are not conductors of electricity.
- Wood and paper are insulators, while petrol is a non-conductive liquid.
- Therefore, the correct answer is option B: Metal.

The electric current always flows from the higher potential to lower potential. The positive terminal of an electric cell is at higher potential with respect to its negative terminal. Hence, in the given circuit, the current will flow from terminal P to terminal N. 

Metal cap is the positive terminal and the metal disc is the negative terminal of the electric cell. An electric cell produces electricity from the chemicals stored inside it.

Circuit is a path through which electric charges flow. A continuous, unbroken path through which electrons can flow is a closed circuit. Charges, or current, can flow only through a closed circuit. A break or opening in a circuit creates an open circuit.

As the electrical energy is used to run blades in the mixer grinder and hence we say in mixer grinder electrical energy is transformed into mechanical energy(rotation of blades).

An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas (plasma).

• In electric bells, electric energy is converted into sound energy.
• When the electric current passes through the coil, it creates a magnetic field that attracts a metal striker, causing it to hit a bell or gong, producing sound.
• Thus, the primary transformation of energy in an electric bell is from electrical to sound energy.


 

 

Petrol and kerosene oil have very low electrical conductivity and hence they are poor electrical conductors (i.e. insulators).

The cylindrical container of an electric cell is made of zinc and acts as the negative terminal.

Zinc is used for the following reasons:

• It is a strong reducing agent.
• It has a lower electrochemical potential compared to other metals.
• This makes it suitable for acting as the negative terminal in electrochemical reactions.

Therefore, the choice of zinc is due to its properties in the electromagnetic series.

The correct answer is Switch. A switch is a device used to control the flow of electrical current in a circuit. It allows the circuit to be:

• Turned on
• Turned off

This effectively breaks or completes the circuit as needed. In relation to electrical systems:

• Earth wire: A component related to safety grounding.
• Live wire: A component responsible for conducting electricity.

Neither the earth wire nor the live wire serves as devices for interrupting circuits.

A break in the filament disrupts the path of the current between the terminals of the electric cell, and as a result, the fused bulb does not light up because no current can pass through its filament.

As electric cell contains chemicals in it which is present as chemical energy the cell converts it into electrical energy and the appliance uses the electrical energy because it cannot use the direct chemicals as there enegy

An electric cell has two terminals: Positive terminal and Negative terminal. Electricity to the bulb in a torch is provided by the electric cell. Electric cells are also used in alarm clocks, wristwatches, transistor radios, cameras and many other devices.