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What are the three main particles that make up an atom?
Proton
Neutron
Electron
Name two examples of conductors and two examples of insulators.
Conductors: copper, aluminum
Insulators: rubber, plastic
What is the difference between a closed circuit and an open circuit?
Closed circuit: A complete path that allows current to flow.
Open circuit: A broken path where current cannot flow.
Define voltage and state its unit of measurement.
Voltage: The electrical potential difference that pushes electrons through a circuit.
Unit: Volt (V)
What are the two types of electric current?
Two types of electric current:
Direct Current (DC)
Alternating Current (AC)
What is the relationship between wire thickness, wire length, and electrical resistance?
Wire thickness, length & resistance:
Longer wire → higher resistance
Thicker wire → lower resistance
Thinner wire → higher resistance
A student wants to design a safe electrical cable. Explain why the cable must have both a conductor in the center and an insulator surrounding it, and what would happen if only one of these materials was used.
The conductor allows electricity to flow efficiently.
The insulator prevents electric shock, short circuits, and energy loss.
Without insulation, electricity could escape and be dangerous. Without a conductor, current would not flow properly.
Compare and contrast how AC generators and DC batteries both provide electrical power to a circuit, considering the direction of electron flow.
DC battery: Provides steady current in one direction.
AC generator: Produces current that reverses direction regularly.
Both supply energy, but electron flow direction differs.
If you increased the number of coils in an electromagnet while keeping the current the same, predict how the magnetic field would change and explain your reasoning.
The magnetic field becomes stronger because each additional coil adds to the total magnetic field strength.
What does one amp equal in terms of electrons per second?
One amp (1 A):
1 amp = 1 coulomb per second, which is approximately 6.24 × 10¹⁸ electrons per second.
List three factors that affect the resistance of a wire.
Three factors affecting resistance:
Length of the wire
Thickness (cross-sectional area)
Material type
How does wrapping a wire into a coil affect the magnetic field created by electric current?
Coiling strengthens the magnetic field because the magnetic fields from each loop add together.
Explain how the structure of an atom relates to why some materials are conductors and others are insulators.
Atom structure & conductivity:
Conductors have loosely held outer (valence) electrons that can move freely. Insulators have tightly bound electrons that cannot move easily.
Describe what happens to electrons when a battery is connected to a closed circuit containing a copper wire.
Electrons in a closed circuit with a battery:
The battery creates an electric field that pushes electrons through the copper wire from the negative terminal to the positive terminal (in DC circuits).
Compare the relationship between voltage and current to the relationship between water pressure and water flow in a pipe.
Voltage is like water pressure.
Current is like the flow rate of water.
Higher pressure (voltage) usually produces greater flow (current).