Unit 2 Review!

Magnetic Forces

100

Two magnets are placed with their north poles facing each other. Predict what will happen and explain why.

• A: They will attract because like poles pull together.
• B: Nothing will happen because they are not touching.
• C: They will repel because like poles push each other away.
• D: They will spin until the poles align.

What is C, "They will repel because like poles push each other away?"

200

A toy car is placed near a magnet, and it moves without being touched. What force is responsible, and how does it work?

• A: Friction; it causes the car to stop moving.
• B: Magnetic force; it acts at a distance to move objects made of certain metals.
• C: Electrical force; it powers the car.
• D: Gravity; it pulls objects toward each other.

What is B, magnetic force; it acts at a distance to move objects made of certain metals?

300

Imagine a magnet is placed in a system of magnetic trains. How would reversing one train’s poles affect the system’s movement?

• A: Trains that repelled might now attract, altering the system’s behavior.
• B: It would increase the speed of the trains.
• C: It would stop all motion.
• D: It would have no effect because the magnetic field remains unchanged.

What is A, Trains that repelled might now attract, altering the system’s behavior?

400

Compare the magnetic force when two magnets are 1 cm apart versus 5 cm apart. What changes, and why? 

• A: The force increases as the distance increases.
• B: The force decreases as the distance increases.
• C: The force disappears when magnets are farther than 5 cm apart.
• D: The force remains the same regardless of distance.

What is B, the force decreases as the distance increases?

500

Why is the force between a magnet and a compass needle stronger near the poles of the magnet?

• A: Magnetic fields weaken near the poles due to interference.
• B: Compass needles are only sensitive to north poles.
• C: Gravity strengthens the force at the poles.
• D: Magnetic fields are strongest at the poles, exerting more force.

What is D, magnetic fields are strongest at the poles, exerting more force?

Magnetic Fields

100

What do magnetic field lines indicate about a magnet?

• A: The magnet’s size and composition.
• B: The strength and direction of the magnetic field.
• C: The temperature and density of the magnet.
• D: The location of the magnet’s energy source.

What is B, the strength and direction of the magnetic field?

200

DOUBLE JEOPARDY!

Why do field lines never cross in a model of a magnetic field?

• A: Crossing lines would indicate multiple directions for the magnetic field at the same point.
• B: Field lines cannot be drawn close to each other.
• C: Field lines crossing would disrupt the magnet’s poles.
• D: Magnetic fields do not interact in that way.

What is A, crossing lines would indicate multiple directions for the magnetic field at the same point?

300

How does Earth’s magnetic field affect navigation tools like compasses?

• A: Compasses weaken Earth’s magnetic field.
• B: Earth’s magnetic field does not affect compasses.
• C: Compasses align with Earth's magnetic field, pointing to the magnetic poles.
• D: Compasses generate their own magnetic fields to find direction.

What is C, compasses align with Earth's magnetic field, pointing to the magnetic poles?

400

Why are magnetic field lines denser near the poles of a magnet?

• A: The poles repel each other, causing denser lines.
• B: Field lines are uniform and do not change density.
• C: The magnetic force weakens at the poles.
• D: The magnetic force is stronger at the poles.

What is D, the magnetic force is stronger at the poles?

500

Predict the field line pattern when two magnets with opposite poles face each other.

• A: The lines will fade out, showing no interaction.
• B: The lines will connect between the poles, showing attraction.
• C: The lines will repel away from the poles, avoiding connection.
• D: The lines will form a circle around the magnets.

What is B, the lines will connect between the poles, showing attraction?

PE & KE

100

What happens to potential energy when a magnet is moved against a magnetic force?

• A: It increases because energy is transferred into the magnetic field.
• B: It decreases because force is applied.
• C: It stays the same since energy cannot be created or destroyed.
• D: It converts directly to heat energy.

What is A, it increases because energy is transferred into the magnetic field?

200

If a magnet pulls a toy car and it starts moving, what type of energy is being demonstrated, and how is it transformed?

• A: Kinetic energy, transformed from the potential energy in the magnetic field.
• B: Potential energy, as it remains stored in the magnetic field.
• C: Gravitational energy, as the car is pulled downward.
• D: Thermal energy, generated by the car’s motion.

What is A, kinetic energy, transformed from the potential energy in the magnetic field?

300

How does the strength of a magnetic field influence the amount of potential energy stored?

• A: Weaker fields store more energy because they are less stable.
• B: Field strength has no effect on potential energy.
• C: Stronger fields store more potential energy when moved against the force.
• D: Stronger fields release energy, reducing potential energy storage.

What is C, stronger fields store more potential energy when moved against the force?

400

A magnet moves away from a system of magnets. Explain how the potential energy changes and why.

• A: Potential energy remains constant because the system’s energy is conserved.
• B: Potential energy increases as the system becomes less stable.
• C: Potential energy decreases because the distance reduces the magnetic force.
• D: Potential energy converts entirely to kinetic energy during the movement.

What is C, potential energy decreases because the distance reduces the magnetic force?

500

Compare the kinetic energy in two magnetic systems where one has more mass. How does mass affect kinetic energy?

• A: Greater mass leads to less kinetic energy if velocity is constant.
• B: Mass reduces the effect of magnetic fields on energy.
• C: Mass has no effect on kinetic energy; only velocity matters.
• D: Greater mass increases kinetic energy if velocity is constant.

What is D, greater mass increases kinetic energy if velocity is constant?

More About Energy

100

What is the Law of Conservation of Energy, and how does it apply to magnetic systems?

• A: Energy cannot be created or destroyed, only transformed and transferred.
• B: Magnetic systems cannot store energy.
• C: Energy in magnetic systems is lost as heat.
• D: Energy can be created and destroyed, changing in form.

What is A, energy cannot be created or destroyed, only transformed or transferred?

200

How can potential energy in a magnetic field be converted into kinetic energy?

• A: By holding a magnet stationary.
• B: By increasing the temperature of the magnet.
• C: By releasing a magnet held against a force.
• D: By removing the magnetic field entirely.

What is C, by releasing a magnet held against a force.

300

Compare energy transformations in two magnets, one with stronger field strength.

• A: The weaker field will transform more energy to compensate for the difference.
• B: Magnetic field strength has no effect on energy transformation.
• C: Both magnets will have the same energy transformations regardless of field strength.
• D: The stronger field will transform more energy, resulting in more kinetic energy.

What is D, the stronger field will transform more energy, resulting in more kinetic energy?

400

How does moving a magnet closer to another stationary magnet affect energy in the system?

• A: Potential energy remains constant, as no work is done.
• B: Potential energy increases due to enhanced magnetic force.
• C: Energy converts directly to heat during the motion.
• D: Potential energy decreases because the distance is reduced.

What is B, potential energy increases due to enhanced magnetic force?

500

A magnetic launcher pushes a ball forward. Explain the transformation of energy in this process.

• A: Magnetic potential energy converts to kinetic energy in the ball.
• B: Kinetic energy is absorbed by the magnetic field.
• C: Thermal energy is released instead of kinetic energy.
• D: Energy transformation does not occur in this process.

What is A, magnetic potential energy converts to kinetic energy in the ball?

Applying Magnetism

100

Why do some animals, like birds, use Earth's magnetic field for navigation?

• A: They generate their own magnetic fields to navigate.
• B: They have metal particles in their cells that align with the field.
• C: They are immune to magnetic forces.
• D: The magnetic field allows them to fly faster.

What is B, they have metal particles in their cells that align with the field?

200

How does a maglev train (magnetic train) use magnetic forces to move?

• A: By using electricity alone.
• B: By converting magnetic energy into heat.
• C: By generating gravity to push the train forward.
• D: By reducing friction using magnetic levitation.

What is D, by reducing friction using magnetic levitation?

300

Why do MRI machines use powerful magnets?

• A: To align hydrogen atoms in the body for imaging.
• B: To eliminate other magnetic fields in the environment.
• C: To generate X-rays for medical use.
• D: To heat tissues for better scans.

What is A, to align hydrogen atoms in the body for imaging?

400

How can an engineer use magnetism to design a faster roller coaster?

• A: By using weaker magnets to avoid repulsion.
• B: By eliminating magnetic forces altogether.
• C: By decreasing the number of magnets in the design.
• D: By increasing field strength and arranging magnets to maximize potential energy.

What is D, by increasing field strength and arranging magnets to maximize potential energy?

500

A spacecraft launcher uses magnets for propulsion. Explain how the design might store and release energy.

• A: Magnets store kinetic energy directly and release it as potential energy.
• B: Energy in the system is lost as the spacecraft moves.
• C: Magnets store potential energy in the field, which converts to kinetic energy during launch.
• D: The system does not involve energy storage.

What is C, magnets store potential energy in the field, which converts to kinetic energy during launch?