Sources & Energy
Name one common source of energy used to produce electricity that a home might use.
Natural gas is a common source of energy used to produce electricity for homes. Homes typically receive this electricity via the power grid, where natural gas powers turbines in plants to generate it.
Define an electric circuit in one sentence.
An electric circuit is a complete, closed loop through which electric current flows from a power source, through conductors and components like resistors or loads, and back to the source.
What is a conductor? Give one example.
A conductor is a material that allows electric current to flow through it easily due to the presence of free-moving electrons. Copper wire is a common example.
Write the standard symbol name for a cell or battery in a circuit diagram (one or two words).
Cell or Battery.
In a series circuit, are components connected one after another or side-by-side? (one word)
One after another.
Give two ways people can reduce electricity use at home (simple actions).
Turn off lights when leaving a room.
Unplug electronics when not in use.
List the four basic components of a simple circuit (use common names).
Power source (e.g., battery).
Wires (conductors).
Load (e.g., bulb).
Switch.
What is an insulator? Give one example.
An insulator is a material that does not allow electric current to flow through it easily because its electrons are tightly bound and cannot move freely. Rubber is a common example.
What symbol is commonly used to show a light bulb in a circuit diagram?
A circle enclosing an X (or cross) is the standard symbol for a light bulb (lamp) in circuit diagrams.
In a parallel circuit, what happens to the current when you add another identical bulb? (short answer)
In a parallel circuit, adding another identical bulb provides an additional path, so the total current from the battery rises (it splits between more branches), while voltage stays the same across each.
Explain one environmental downside of producing electricity from coal.
One key environmental downside of producing electricity from coal is its high carbon dioxide emissions, which significantly contribute to climate change and global warming.
What is the difference between an open circuit and a closed circuit?
An open circuit has a break or gap (like an off switch), preventing electric current from flowing, so no power reaches the load. A closed circuit forms a complete, continuous loop, allowing current to flow from the power source through the components and back, powering devices like a light bulb.
Explain why metals like copper allow electric current to flow.
Metals like copper allow electric current to flow because they contain free or delocalised electrons in their atomic structure that are not tightly bound to any single atom, enabling these electrons to move easily through the metal lattice when a voltage is applied.
Why do engineers and electricians use circuit diagrams? Give one clear reason.
Engineers and electricians use circuit diagrams to visually represent and standardise electrical connections, making it easier to design, build, troubleshoot, and maintain circuits without needing the physical setup.
If two identical bulbs are wired in series with one battery, what happens to their brightness compared to a single bulb on the same battery? Explain briefly.
They become dimmer. With two identical bulbs in series, the battery voltage splits equally across both (halving the power to each), and total resistance doubles, reducing current through the circuit compared to a single bulb, so each glows less brightly.
Describe briefly how wind turbines produce electricity (one or two sentences).
Wind turbines produce electricity when wind spins the large blades, which turn a rotor connected to a generator via a shaft and gearbox. The generator then converts this mechanical energy into electrical current through electromagnetic induction.
Explain in one sentence how electric current flows through a circuit (use component names).
Electric current flows from the positive terminal of a power source like a battery, through conducting wires and a closed switch, past the load such as a bulb, and returns to the negative terminal, completing the circuit loop.
You test three materials (plastic, aluminum foil, and wood) in a simple circuit. Which two are most likely to let current flow? Explain briefly.
Aluminum foil and only aluminum foil would let current flow; plastic and wood are insulators that resist electricity due to tightly bound electrons, while aluminum, a metal, conducts well thanks to its free-moving electrons.
List two rules or conventions for drawing neat circuit diagrams (e.g., how to show connections).
Draw straight lines between components to show connections, using dots at junctions where lines meet.
Place components from left to right following signal flow, with inputs on the left and outputs on the right.
Explain why one bulb can stay lit in a parallel circuit even if another parallel branch is opened.
In a parallel circuit, each bulb has its own independent path to the battery, so opening one branch (e.g., removing or switching off a bulb) breaks current flow only in that path, leaving the voltage across other branches unchanged and allowing the remaining bulb(s) to stay lit normally.
Compare energy efficiency and energy conservation. Give an example of each.
Energy efficiency involves using technology or better processes to deliver the same service with less energy input, such as replacing incandescent bulbs with LEDs that produce equivalent light using about 75% less electricity.
In contrast, energy conservation reduces overall energy consumption by changing behaviours or habits, like turning off lights when leaving a room to avoid unnecessary usage.
Name two safety precautions to follow when building or testing simple circuits.
Use low-voltage batteries (e.g., 1.5V) only.
Disconnect power before making changes.
Design a simple experimental step (two sentences) to test whether a material is a conductor or an insulator using a battery, bulb, wires, and clips.
Connect the battery, wires with clips, and bulb into a basic closed circuit to confirm it lights up. Insert the test material between two clips in the circuit; if the bulb lights, it is a conductor, but if not, it is an insulator.
Draw (describe in words) a simple circuit diagram that includes a battery, switch, and bulb in a closed path. Label each component in your description.
Start with a long line parallel to a short line (battery, positive on left).
Connect positive to switch gap (closed), then to bulb circle with X inside, back to negative.
You have two identical bulbs and two identical batteries. Describe (one or two sentences) how brightness would compare if bulbs are arranged (a) both in series on one battery, (b) each bulb on its own battery.
In (a), both bulbs dim compared to a single bulb, as voltage splits and current halves. In (b), each bulb shines at full brightness, matching a single bulb on one battery.