Electricity/Magnetism 5th

The picture below shows an incomplete circuit. How can this circuit be completed?

• Attach the wires

• Flip the switch open

• Move the battery closer to the bulb

• Flip the battery to reverse the charges

Answer explanation

To complete the circuit, the wires must be attached to connect the components. This allows electricity to flow, enabling the circuit to function properly. The other options do not complete the circuit.

Which materials are good conductors of electricity?

• Nail and fabric

• Nail and gold nugget

• Wooden toothpick and fabric

• Wooden toothpick and gold nugget

Answer explanation

Nail and gold nugget are good conductors of electricity. Metals like gold and iron (found in nails) allow electric current to flow easily, while materials like fabric and wood are insulators and do not conduct electricity.

Which of these objects will be attracted to a magnet?

• Wax crayon

• Rubber eraser

• Metal paper clip

• Plastic building block

Answer explanation

The metal paper clip is attracted to a magnet because it is made of ferromagnetic material, which responds to magnetic fields. The other objects—wax crayon, rubber eraser, and plastic building block—are not magnetic.

Aubri and Nevaeh rub identical balloons against their hair, creating negative charges. What will happen when they bring their balloons close together?

• The balloons will repel each other because they have the same charge.

• The balloons will attract each other because they have the same charge.

• The balloons will lose their charge and become neutral.

• One balloon will transfer its charge to the other.

Answer explanation

The balloons will repel each other because they both have negative charges. Like charges repel, while opposite charges attract. Since both balloons are negatively charged, they will push away from each other.

A student places a wooden board between two magnets, and they do not attract each other. Why?

• The wooden board is too thick.

• The magnets are too big.

• The magnetic field is blocked by the wood.

• Magnets do not work through materials.

Answer explanation

The wooden board is too thick, preventing the magnetic field from effectively reaching the other magnet. This thickness blocks the attraction, which is why the magnets do not attract each other.

Which of the following completes a simple electric circuit?

• A. A battery, wires, and an open switch

• B. A battery, wires, and a closed switch

• C. A battery, wires, and plastic

• D. A battery, wires, and a magnet

Answer explanation

A closed switch allows current to flow, completing the circuit. Option B includes a battery, wires, and a closed switch, making it the correct choice. The other options either have an open switch or components that do not complete a circuit.

Paris wants to determine if an unknown material is a metal. Which observation would best confirm and help Paris determine that the material is a metal?

• It is a good conductor of electricity.

• It can break easily and is very brittle.

• It can easily float in water.

• It is brown and dull.

Answer explanation

The best observation to confirm a material is a metal is its ability to conduct electricity well, as metals are typically good conductors. The other options suggest properties of non-metals or do not specifically indicate metallic characteristics.

Which of the following is the best electrical conductor?

• Cotton ball

• Metal nickel

Answer explanation

Metal nickel is a good electrical conductor due to its free-moving electrons, allowing electricity to flow easily. In contrast, a cotton ball is an insulator and does not conduct electricity.

What do we call a material that does not allow electricity to pass through it easily?

• Insulator

• Conductor

• Radiator

• Reflector

Answer explanation

An insulator is a material that does not allow electricity to pass through it easily, making it the correct choice. In contrast, a conductor allows electricity to flow, while radiator and reflector are unrelated terms.

Which item would be attracted to a magnet?

• A. A wax crayon

• B. A rubber eraser

• C. A metal paper clip

• D. A plastic building block

Answer explanation

A metal paper clip is made of ferromagnetic material, which is attracted to magnets. In contrast, a wax crayon, rubber eraser, and plastic building block are non-metallic and not magnetic.