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MassachusettsPhysics

Module 6: Electricity and magnetism

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is electric current, what drives it, what resists it, and how does Ohm's law connect them?

Define electric current, voltage, and resistance, and use Ohm's law V = IR to relate them in a simple circuit (MA STE Introductory Physics, electric circuits).
A standard-level answer on current and Ohm's law for the Massachusetts High School Introductory Physics MCAS: current as the flow of charge, voltage as the push that drives it, resistance as what opposes it, and using the reference-sheet relationship V = IR in a simple circuit.
12 min answer →

What is electric charge, how do charged objects exert forces on each other, and how does that force depend on charge and distance?

Describe positive and negative charge and that like charges repel and unlike charges attract, and use Coulomb's law qualitatively (force proportional to the charges and inversely proportional to the square of the distance) (MA STE Introductory Physics, Motion and Forces, HS-PS2-4).
A standard-level answer on electric charge and Coulomb's law for the Massachusetts High School Introductory Physics MCAS (HS-PS2-4): positive and negative charge, like charges repelling and unlike charges attracting, and how the electric force depends on the charges and the inverse square of the distance.
12 min answer →

How much energy does a circuit transfer each second, and how is electrical power calculated?

Define electrical power as the rate at which a circuit transfers energy, use P = IV (and energy E = Pt), and connect electrical power to the transformation of electrical energy into other forms (MA STE Introductory Physics, electric circuits, Energy).
A standard-level answer on electrical energy and power for the Massachusetts High School Introductory Physics MCAS: electrical power as the rate of transferring energy, the reference-sheet relationship P = IV, finding energy as power times time, and how circuits transform electrical energy into light, heat, and motion.
12 min answer →

How does a changing magnetic field create an electric current, and how do generators use this to make electricity?

Explain electromagnetic induction (a changing magnetic field produces a current in a conductor) and how a generator converts kinetic energy into electrical energy (MA STE Introductory Physics, Motion and Forces, Energy, HS-PS2-5, HS-PS3-5).
A standard-level answer on electromagnetic induction for the Massachusetts High School Introductory Physics MCAS (HS-PS2-5, HS-PS3-5): how a changing magnetic field induces a current in a conductor, what makes the induced current larger, and how a generator converts kinetic energy into electrical energy.
12 min answer →

How do magnets behave, what is a magnetic field, and how does an electric current produce one?

Describe magnetic poles and fields, state that like poles repel and unlike poles attract, and explain that an electric current produces a magnetic field (the basis of electromagnets) (MA STE Introductory Physics, Motion and Forces, HS-PS2-5).
A standard-level answer on magnetism and magnetic fields for the Massachusetts High School Introductory Physics MCAS (HS-PS2-5): magnetic poles, like poles repelling and unlike attracting, the magnetic field around a magnet, and how an electric current produces a magnetic field in an electromagnet.
12 min answer →

How do current, voltage, and resistance behave differently in series and parallel circuits?

Compare series and parallel circuits: in series the current is the same and voltage divides; in parallel the voltage is the same and current divides, and adding parallel branches lowers the total resistance (MA STE Introductory Physics, electric circuits).
A standard-level answer on series and parallel circuits for the Massachusetts High School Introductory Physics MCAS: how current is the same and voltage divides in series, how voltage is the same and current divides in parallel, how total resistance changes, and why homes are wired in parallel.
13 min answer →