CP: 2FF FEM Les. 2: Flow of Electricity

The flow of electricity in a certain path is called -

• a source of energy

• a circuit

• a current

• all of the above

Answer explanation

The question asks about the term for the flow of electricity in a specific path. The correct answer is 'a current'. A current refers to the flow of electrons in a circuit. The other options, 'a source of energy' and 'a circuit', are related to electricity but do not accurately describe the flow of electricity.

Which of the following is a good conductor of electricity?

• Rubber

• Water

• Plastic

• Glass

Answer explanation

Water is a good conductor of electricity due to the presence of ions in it. When water molecules dissociate, they produce ions that can carry an electric charge. In contrast, rubber, plastic, and glass are insulators, meaning they do not allow the flow of electricity. Insulators have tightly bound electrons that prevent the movement of electric charge.

A light bulb is connected to a closed circuit. Which answer best describes what will happen?

• The light bulb will turn on.

• The light bulb will not turn on.

• The light bulb will open the circuit.

• Electricity wil not flow in the circuit.

Answer explanation

In a closed circuit, the electrical components are connected in a complete loop, allowing electricity to flow through them. When a light bulb is connected to a closed circuit, it completes the loop, and electricity flows through the filament, causing it to heat up and emit light. Therefore, the light bulb will turn on.

Why are electrical wires made of metal and usually coated in plastic?

• Metal and plastic are both good conductors of electricity.

• Metal is a good conductor of electricity and plastic is a good insulator.

• Metal and plastic are both electrical insulators.

• Metal is a good insulator and plastic is a good conductor of electricity.

Answer explanation

The question asks why electrical wires are made of metal and coated in plastic. The correct answer is that metal is a good conductor of electricity, which means it allows electricity to pass through it easily. On the other hand, plastic is a good insulator, which means it prevents electricity from passing through. Therefore, the metal core carries the electrical current, while the plastic coating provides safety by preventing unwanted electrical discharges.

Which statement best explains why copper is useful in constructing electrical circuits?

• It can be turned into wire and it can be used to form a complete path for electrical current to pass.

• It can be turned into wire and it can be used to prevent electrical current from passing.

• When electrical current passes through it, the current turns into heat, light, and sound.

• When electrical current passes through it, the copper increases the amount of current.

Answer explanation

Copper is useful in constructing electrical circuits because it can be easily turned into wire, allowing it to form a complete path for electrical current to pass. This property makes it an excellent conductor of electricity, which is essential for efficient and effective electrical circuits.

Which of the following set of items could be used to make a complete circuit that produces light?

• Battery, copper wires, switch

• Copper wires, light bulb, bell

• Battery, copper wires, light bulb

• Copper wires, switch, bell

Answer explanation

A complete circuit that produces light requires a power source, a conductor, and a load. In this case, the battery serves as the power source, copper wires act as conductors, and the light bulb is the load. The combination of these three items creates a complete circuit, allowing the light bulb to illuminate.

Tags

NGSS.3-5-ETS1-1

NGSS.3-5-ETS1-2

Which of the following is necessary for electricity to flow through an electric circuit?

• The wires must be insulated.

• The path of the electricity must be complete.

• At least two batteries must be used.

• A switch must be used to allow the flow.

Answer explanation

For electricity to flow through an electric circuit, the path must be complete. This allows electrons to move from one end of the circuit to the other, creating an electric current. Insulation, multiple batteries, and switches can be part of a circuit, but they are not necessary for the flow of electricity.

A student assembles a circuit for science class.

Which of the following best explains why the bulb is not lit in this circuit?

• The battery is not long enough to connect the wires.

• Wire X needs to be connected to the top of the battery.

• A third wire should be added from the bottom of the battery to the bulb.

• A second battery needs to be added to the circuit.

Answer explanation

The bulb is not lit in the circuit because Wire X is not connected to the top of the battery. This connection is necessary to complete the circuit and allow the flow of electricity, which would light up the bulb. The other options do not address the issue of an incomplete circuit.

An electric circuit is shown.

If both bulbs are lit, which of the following is true?

• Both Item X and Item Y are made of metal.

• Item X is made of metal and Item Y is made of plastic.

• Both Item X and Item Y are made of plastic.

• Item X is made of plastic and Item Y is made of metal.

Answer explanation

For both bulbs to be lit in an electric circuit, there must be a continuous flow of electricity. This can only happen if both Item X and Item Y are made of metal, as metals are good conductors of electricity. If either item were made of plastic, which is an insulator, the circuit would be incomplete and the bulbs would not light up.

Tags

NGSS.MS-PS3-5

Match the following vocabulary and definitions

• insulator

• a substance that allows electricity or heat to easily pass through it

• battery

• a substance that does not allow electricity or heat to easily pass through it

• conductor

• a source of electrical energy