Practical Electricity - Pre-lesson Quiz

1. Where must be the fuse be placed?

At the earth wire

At the live wire

At the neutral wire

None of the above

The fuse must be placed at the live wire because it acts as a safety device that protects electrical circuits from overloading or short-circuiting. By placing the fuse at the live wire, it can interrupt the flow of current in case of any faults or excessive current, preventing damage to the circuit or appliances and reducing the risk of electrical fires or accidents.

Explanation

The fuse must be placed at the live wire because it acts as a safety device that protects electrical circuits from overloading or short-circuiting. By placing the fuse at the live wire, it can interrupt the flow of current in case of any faults or excessive current, preventing damage to the circuit or appliances and reducing the risk of electrical fires or accidents.

2. What is the power generated when a current of 6 A pass through a resistor with a potential difference of 2 V across it?

0.33 W

3 W

8 W

12 W

The power generated when a current of 6 A passes through a resistor with a potential difference of 2 V across it can be calculated using the formula P = IV, where P is power, I is current, and V is potential difference. Plugging in the given values, we get P = 6 A * 2 V = 12 W. Therefore, the correct answer is 12 W.

Explanation

The power generated when a current of 6 A passes through a resistor with a potential difference of 2 V across it can be calculated using the formula P = IV, where P is power, I is current, and V is potential difference. Plugging in the given values, we get P = 6 A * 2 V = 12 W. Therefore, the correct answer is 12 W.

3. What colour is the earth wire?

Brown

Blue

Black

Green and yellow

The earth wire is typically colored green and yellow. This color combination is used to easily identify and distinguish the earth wire from other wires in an electrical system. The purpose of the earth wire is to provide a safe path for electrical current to flow into the ground in case of a fault or electrical surge, preventing electric shock or damage to appliances.

Explanation

The earth wire is typically colored green and yellow. This color combination is used to easily identify and distinguish the earth wire from other wires in an electrical system. The purpose of the earth wire is to provide a safe path for electrical current to flow into the ground in case of a fault or electrical surge, preventing electric shock or damage to appliances.

4. What is the amount of energy used when a 500 W television is used 4 hours a day for 30 days?

60 kWh

240 kWh

3750 kWh

60,000 kWh

The amount of energy used can be calculated by multiplying the power of the television (500 W) by the number of hours it is used per day (4 hours) and the number of days it is used (30 days). This gives us a total energy consumption of 60,000 watt-hours or 60 kWh.

Explanation

The amount of energy used can be calculated by multiplying the power of the television (500 W) by the number of hours it is used per day (4 hours) and the number of days it is used (30 days). This gives us a total energy consumption of 60,000 watt-hours or 60 kWh.

5. Which of the following wires are used in heating elements?

Steel

Copper

Nichrome

Tungsten

Nichrome wires are commonly used in heating elements because they have a high melting point, high resistivity, and can withstand high temperatures without oxidizing or corroding easily. This makes them ideal for heating applications where a consistent and controlled amount of heat is required. Steel, copper, and tungsten wires are not typically used in heating elements due to their lower resistivity or other limitations.

Explanation

Nichrome wires are commonly used in heating elements because they have a high melting point, high resistivity, and can withstand high temperatures without oxidizing or corroding easily. This makes them ideal for heating applications where a consistent and controlled amount of heat is required. Steel, copper, and tungsten wires are not typically used in heating elements due to their lower resistivity or other limitations.