Electric Circuits - SEC 2nt

Silver is a good conductor of electricity because it has a high number of free electrons that can move easily through its structure. This allows electric current to flow easily through silver. In contrast, eraser, plastic ruler, and rubber band are insulators and do not allow the flow of electric current. Therefore, the silver fork is the only example in the given options that is an electrical conductor.

The symbol "an open switch" represents a switch that is not connected, meaning that the circuit is open and no current can flow through it.

If the switch in the diagram is open, it means that there is no complete circuit for the flow of electricity. Without a closed circuit, the current cannot reach the light bulb, and therefore it will not light up.

When a switch is closed, it means that electricity can flow through the switch. Closing a switch completes the circuit, allowing electricity to flow from the power source through the switch and into the connected devices or components. This allows the electrical current to continue its path and power the devices that are connected to the circuit.

To form a complete circuit and light up the light bulb, a cell is needed. A cell is a device that converts chemical energy into electrical energy, providing the necessary power source for the circuit. Without a cell, there would be no electricity flowing through the wires to power the light bulb, and therefore it would not light up. A switch, resistor, or piece of iron are not essential components for the light bulb to light up, although they may be used for other purposes in a circuit.

Adding one more cell in series to the circuit will increase the brightness of the light bulb. When cells are connected in series, their voltages add up, resulting in a higher total voltage across the circuit. This increased voltage will cause more current to flow through the light bulb, leading to a brighter glow.

Iron is a conductor of electricity because it has free electrons that can move easily through its structure, allowing electric current to flow. Wood, on the other hand, is an insulator of electricity because it does not have free electrons and does not allow electric current to flow easily. Therefore, the list "iron, wood" contains one conductor (iron) and one insulator (wood) of electricity.

The given symbol represents a resistor. A resistor is an electrical component that limits the flow of electric current in a circuit. It is usually represented by a zigzag line in circuit diagrams. Resistor values are measured in ohms and they are used to control the amount of current flowing through a circuit, regulate voltage levels, and dissipate heat.

In order for light bulb A to light up, switches a and c need to be closed, and switch b needs to be open. This means that the circuit needs to be completed through switches a and c, while switch b needs to break the circuit for light bulb B.

If too many cells are added to the circuit, the increased voltage may cause the light bulb to burn out. This is because the excess voltage can generate excessive heat, leading to the filament in the light bulb becoming too hot and eventually burning out.