Which of the following is an example of an electric force?

• The attraction between opposite poles of a magnet

• The repulsion between two like charges

• The magnetic field around a wire carrying current

• The motion of an electric motor

Answer explanation

Electric forces act between charged particles. Like charges repel, and opposite charges attract.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Which of the following devices uses magnetic fields to generate electricity?

• Light bulb

• Generator

• Battery

• Capacitor

Answer explanation

A generator uses magnetic fields and motion to produce electricity through electromagnetic induction.

Tags

NGSS.MS-PS2-5

In everyday appliances, what is the primary function of a motor?

• To convert electrical energy into kinetic energy

• To store energy

• To convert kinetic energy into electrical energy

• To produce heat

Answer explanation

Motors use electricity to produce motion (kinetic energy), often in fans, blenders, or wheels.

Tags

NGSS.MS-PS3-5

In a transformer, the changing current in the primary coil creates what?

• A. A constant voltage

• B. An electric charge in the primary coil

• C. Heat

• D. A magnetic field in the secondary coil

Answer explanation

A transformer works through electromagnetic induction; the changing current in the primary coil creates a magnetic field that induces a voltage in the secondary coil.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

What is the result of placing a magnet near a moving conductor?

• It generates an electric current

• It causes the magnet to repel

• It causes the conductor to heat up

• It generates a force that resists the motion

Answer explanation

According to Faraday’s Law, a magnet near a moving conductor induces current in the conductor.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

After your lab partner drops a magnet you are using in the lab on the ground it breaks into 3 separate pieces before you complete all the steps in the experiment. What will be the outcome of your experiment if you continue using the pieces of the broken magnet individually?

• The experiment will have significant errors since the magnetism will be lost to the environment.

• The experiment will have significant errors since each broken piece will be either a north pole or a south pole.

• The experiment will have no significant error only if you tape the pieces back together forming a whole magnet.

• The experiment will have no significant errors since the pieces will be complete magnets with two poles just like the original magnet.

Answer explanation

When a magnet is broken, each piece forms a new complete magnet with both north and south poles.

A mass attached to a spring oscillates with a period of 2 seconds. What will happen if the mass is doubled?

• The period will increase.

• The period will decrease.

• The period will remain the same.

• The frequency will increase.

Answer explanation

Explanation: For mass-spring systems, the period increases with mass.

What variable is the period of a simple pendulum dependent upon?

• The mass of the pendulum

• The amplitude of the swing

• The length of the pendulum and the acceleration due to gravity

• The force applied to the pendulum

Answer explanation

The period of a simple pendulum depends only on its length and gravity

A wave travels through a rope, and a pulse is created by moving one end of the rope up and down. What type of wave is this?

• Longitudinal wave

• Transverse wave

• Surface wave

• Electromagnetic wave

Answer explanation

In a rope, particles move perpendicular to the wave direction—this defines a transverse wave.

Tags

NGSS.MS-PS4-1

What is required for the propagation of a mechanical wave?

• A medium that can transmit the wave energy

• A source of electrical energy

• A vacuum

• A steady temperature

Answer explanation

Mechanical waves (like sound or water waves) need a medium (air, water, solid) to travel.

Tags

NGSS.MS-PS4-2