← Physics syllabus

WalesPhysics

Unit 4 Fields and their Applications

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does a capacitor store charge and energy, and why are charge and discharge exponential?

Capacitance and the charge stored, the energy stored in a capacitor, and exponential charge and discharge through a resistor with time constant RC.
A focused answer to WJEC A-Level Physics Unit 4 capacitance, covering capacitance and the charge stored, the energy stored in a capacitor, and the exponential charge and discharge of a capacitor through a resistor with time constant RC.
11 min answer →

How does a changing magnetic flux induce an EMF, and what sets its size and direction?

Magnetic flux and flux linkage, Faraday's law, Lenz's law, and applications in generators and transformers.
A focused answer to WJEC A-Level Physics Unit 4 electromagnetic induction, covering magnetic flux and flux linkage, Faraday's law for the induced EMF, Lenz's law for its direction, and applications in generators and transformers.
11 min answer →

How are electric and gravitational fields alike, and how do field strength and potential vary with distance?

Coulomb's law and Newton's law of gravitation, electric and gravitational field strength and potential, and the inverse-square nature of both fields.
A focused answer to WJEC A-Level Physics Unit 4 electrostatic and gravitational fields, covering Coulomb's law and Newton's law of gravitation, electric and gravitational field strength and potential, and the inverse-square nature shared by both fields.
11 min answer →

What force does a magnetic field exert on a current and on a moving charge?

Magnetic flux density, the force on a current-carrying conductor, the force on a moving charge, and Fleming's left-hand rule.
A focused answer to WJEC A-Level Physics Unit 4 magnetic fields, covering magnetic flux density, the force on a current-carrying conductor (the motor effect), the force on a moving charge, and using Fleming's left-hand rule.
11 min answer →

How does gravity govern orbits, and what does the wider universe reveal about mass we cannot see?

Circular orbits under gravity, Kepler's third law, satellites and escape, and evidence for dark matter from galactic rotation.
A focused answer to WJEC A-Level Physics Unit 4 orbits and the wider universe, covering circular orbits under gravity, Kepler's third law, satellites, and the evidence for dark matter from galactic rotation curves.
11 min answer →