Electrical Energy Revision Quiz

The continuous movement of electrons in a wire is called:

• an electric circuit

• an electric current

• electrical resistance

• an electrical conductor

Answer explanation

The continuous movement of electrons in a wire is referred to as an electric current. This term specifically describes the flow of electric charge, distinguishing it from other concepts like resistance or conductors.

Electric current is measured using an ammeter, in units called:

• ohms (Ω)

• amperes (amps, A)

• volts (V)

• watts (W)

Answer explanation

Electric current is specifically measured in amperes (amps, A). Ohms (Ω) measure resistance, volts (V) measure voltage, and watts (W) measure power. Therefore, the correct unit for current is amperes.

Which of these forms of electromagnetic radiation has the shortest wavelength?

• gamma rays

• microwaves

• radio waves

• ultraviolet

Answer explanation

Gamma rays have the shortest wavelength in the electromagnetic spectrum, making them more energetic than microwaves, radio waves, and ultraviolet radiation.

Which one of the following sentences is true?

• Conductors are usually plastic, rubber, wood, glass, porcelain or air.

• Insulators are usually metals like silver, copper, gold, aluminium or steel.

• Conductors are usually metal because the electrons are only weakly attracted to the nuclei of the atoms, so they are free to skip from atom to atom.

• Insulators are usually metal because the electrons are only weakly attracted to the nuclei of the atoms, so they are free to skip from atom to atom.

Answer explanation

The correct choice states that conductors are usually metal because their electrons are weakly attracted to the nuclei, allowing them to move freely. This is true, while the other options incorrectly describe conductors and insulators.

Which form of electromagnetic radiation is used in remote controls?

• infrared

• microwaves

• visible light

• X-rays

Answer explanation

Remote controls use infrared radiation to transmit signals. Infrared waves are not visible to the human eye but can be detected by sensors in devices, making them ideal for remote control functionality.

Resistors made of substances such as platinum, nichrome, tungsten, iron and carbon....:

• increase the current flowing through the conductor

• reduce the amount of vibration in the conductor

• reduce the amount of vibration of the atoms in the conductor, decrease the temperature of the conductor and reduce the current flowing through the conductor

• increase the amount of vibration of the atoms in the conductor, increase the temperature of the conductor and reduce the current flowing through the conductor

Answer explanation

Resistors made of materials like platinum and nichrome increase atomic vibrations, raising the conductor's temperature. This increased resistance reduces the current flowing through the conductor.

An electronic device, made of small pieces of silicon that allows a current to flow in one direction but not the other, is called…:

• a transistor

• a capacitor

• a diode

• an integrated circuit

Answer explanation

A diode is a semiconductor device that allows current to flow in one direction only, making it the correct answer. Transistors and capacitors serve different functions, while integrated circuits are more complex assemblies.

House wiring is usually done in a…:

• parallel circuit

• series circuit

• parallel or series circuit

• none of the above

Answer explanation

House wiring is usually done in a parallel circuit to ensure that each device receives the same voltage and can operate independently. This allows for better safety and functionality compared to a series circuit.

Which of the following is true?

• Two bulbs wired in a series circuit glow as brightly as if there were only one.

• Two bulbs wired in a parallel circuit glow as brightly as if there were only one.

• Each bulb wired in a parallel circuit glow more dimly because the electrons meet more resistance.

• The electrons in a series circuit meet less resistance than in a parallel circuit.

Answer explanation

In a parallel circuit, each bulb receives the full voltage, allowing them to glow as brightly as a single bulb. In contrast, bulbs in a series share the voltage, resulting in dimmer light.

Parallel circuits are more useful, for example in house wiring, because…:

• less wiring is required

• the source of electrons has to push the current through each resistor

• each branch operates independently

• there is more resistance

Answer explanation

In parallel circuits, each branch operates independently, allowing devices to function separately. This means if one device fails, others remain unaffected, making parallel circuits ideal for house wiring.