Revision Quiz On Electricity

The correct colour of the Earth wire is yellow and green. This is because the Earth wire is used for grounding electrical systems and providing a safe path for electrical current to flow in the event of a fault. The yellow and green colour is internationally recognized as the standard colour for Earth wires, indicating that it is specifically designated for grounding purposes. Using any other colour for the Earth wire could lead to confusion and potential safety hazards.

Current is the rate of flow of charge. It refers to the movement of electric charge through a conductor. In other words, it is the flow of electrons in a circuit. Current is measured in amperes (A) and is represented by the symbol "I". It is an essential concept in understanding and analyzing electrical circuits and is used to calculate power, voltage, and resistance in a circuit.

In a series circuit, the current remains the same throughout. Therefore, if the current passing through the first bulb is 3 A, then the current passing through the second and last bulb will also be 3 A, not 2 A and 1 A respectively. Hence, the statement is false.

The statement is true because the SI unit of charge is indeed coulomb, which is represented by the symbol C. The coulomb is a fundamental unit of electric charge in the International System of Units (SI). It is defined as the amount of electric charge transported by a constant current of one ampere in one second. Therefore, the correct answer is true.

When bulbs are connected in series, the same current flows through each bulb. According to Ohm's Law, the potential difference across a resistor is directly proportional to its resistance. Since the potential difference across each bulb is the same, it implies that the resistance of each bulb must also be the same. Therefore, the statement is true.

The earth wire is connected to the ground, which is considered to be at zero potential. This means that any electrical charge or current that flows through the earth wire will be neutralized and dissipated into the ground, preventing any potential harm or damage. Therefore, the statement that the earth wire is at zero potential is true.

The fuse should be connected to the live wire. This is because the live wire carries the current from the power source to the appliance or device. By connecting the fuse to the live wire, it acts as a safety measure to protect against excessive current flow and prevent damage to the circuit or device.

A voltmeter has high resistance because it is designed to measure voltage without drawing significant current from the circuit being measured. High resistance ensures that the voltmeter does not interfere with the circuit and accurately measures the voltage across the component or circuit under test.

The correct color of the Live wire is brown. In electrical wiring, the Live wire carries the current from the power source to the electrical device. The color coding of wires is standardized to ensure safety and consistency. In most countries, including the UK and Europe, the Live wire is typically brown. This color helps electricians and technicians identify and differentiate the Live wire from other wires in the circuit.

When bulbs are connected in parallel, the voltage across each bulb is the same, which means the current flowing through each bulb is also the same. According to Ohm's Law (V = IR), if the current is the same and the voltage is the same, then the resistance must be the same as well. Therefore, the statement is true.

When bulbs are connected in parallel, each bulb has its own branch and receives the same potential difference across it. This is because the potential difference is shared equally among the branches. Therefore, even if the bulbs have different resistance, the potential difference across each bulb will still be the same.

The resistance of an ohmic metal wire is determined by its length, material, and cross-sectional area. However, the potential difference supplied across the wire does not affect its resistance. This is because resistance is a property inherent to the wire itself and is not influenced by external factors such as the potential difference.

The correct answer is "volt (V)". Volt is the SI unit for potential difference, which measures the amount of electric potential energy per unit charge. It represents the amount of work needed to move a unit charge between two points in an electric field.

The correct answer is low, negligible. An ammeter is a device used to measure electric current in a circuit. It needs to have low resistance in order to minimize the amount of voltage drop across it and to accurately measure the current flowing through the circuit. Negligible resistance means that the ammeter will not significantly affect the current being measured.

When bulbs are connected in parallel, the total resistance of the circuit is calculated by adding the reciprocals of the individual resistances. In this case, the effective resistance is given as 3 ohms. Since the three bulbs are identical, the resistance of each bulb can be calculated by dividing the total resistance by the number of bulbs, which is 3. Therefore, the resistance of each bulb is 9 ohms.

The correct answer is that the switch of an appliance can be installed at the live wire or the neutral wire. This statement is incorrect because the switch of an appliance should only be installed at the live wire. The neutral wire is meant to carry the return current back to the source, and it should not be interrupted by a switch. Installing a switch on the neutral wire can create a dangerous situation where the appliance may still be energized even when the switch is turned off.

The correct answer states that power is the rate at which energy is changed from one form to another, and that power is equal to voltage multiplied by current. This explanation aligns with the principles of electrical power, as power is indeed the rate at which energy is transformed or converted, and the formula P = VI represents the relationship between power, voltage, and current in electrical systems.