Test: Electricity - Year 4 MCQ

Distilled water is pure and free of dissolved salts, which means it lacks the ions necessary to conduct electricity. In contrast, tap water typically contains various impurities and dissolved salts, making it a better conductor of electric current.

Plastic is widely used as an insulating material in electrical appliances. It effectively prevents electric current from escaping and protects users from electric shock, ensuring safe operation of devices.

An insulator is a material that resists the flow of electricity. Plastic is a common insulator used in electrical appliances to protect users from electric shock. It prevents electricity from passing through, ensuring safe handling of devices.

A switch functions as a control mechanism in an electrical circuit, allowing users to open or close the circuit. By closing the switch, the circuit is completed, enabling current to flow, while opening it breaks the circuit and stops the flow of electricity.

When more cells are added to a circuit, the voltage increases, providing more energy to the circuit. This results in the lamps shining more brightly because they receive a greater amount of electric current.

A conductor is defined as a material that allows electricity to flow through it easily. Common examples include metals like copper and aluminum, which are widely used in electrical wiring and components due to their efficiency in conducting electric current.

It is vital to turn off the power before touching any electrical wires. This practice helps prevent electric shock and ensures safety while working on or near electrical circuits. Always handling wires with care and using appropriate tools can significantly reduce the risk of accidents.

The human body contains a significant amount of water, approximately 65%, and this water includes dissolved salts, which enable the body to conduct electricity. This is why it is crucial to avoid electrical hazards, especially when wet.

Mains electricity poses significant risks, including the potential for severe burns, heart failure, or even death due to electric shock. Understanding these risks highlights the importance of using proper safety precautions when working with electrical systems.

Pylons are structures that support the overhead power lines carrying high-voltage electricity from power stations to homes and businesses. They are essential for the distribution of electricity across long distances.

A conductor is a material that allows electricity to flow through it easily. Copper is a prime example of a conductor, widely used in electrical wiring and components due to its excellent conductivity. In contrast, materials like plastic and wood are insulators, which means they do not conduct electricity. Understanding the properties of conductors is crucial for safe and effective electrical system design.

The primary function of a switch in an electrical circuit is to control the flow of electric current. By opening or closing the circuit, switches allow users to turn devices on or off without physically disconnecting wires. This functionality is essential for safe and convenient operation of electrical appliances, as it provides a simple means to manage electrical energy.

Natural water, such as that from rivers or taps, contains dissolved salts which dissociate into ions, allowing it to conduct electricity. In contrast, distilled water is purified and contains no dissolved salts, making it a poor conductor. This distinction is important, especially in safety discussions around handling water near electrical devices, as the presence of ions in natural water can enhance conductivity and increase the risk of electric shock.

It is crucial to strip insulation from electrical wires carefully, ensuring that you do so away from your body to avoid injury. This practice minimizes the risk of electric shock and protects you from potential accidents. Additionally, using non-conductive tools when working with electrical components can further enhance safety, highlighting the importance of proper techniques in electrical work.

When more cells are added to a circuit, the overall voltage increases, providing more energy to the circuit. This additional energy allows the lamps to shine more brightly as they receive a higher voltage. Conversely, adding more lamps without increasing the voltage can divide the available energy among them, causing each lamp to shine dimmer. This principle is fundamental in understanding how electric circuits function and how to effectively manage their components for desired outcomes.