Physics: should I choose it?

How are light and heat explained?

How is energy from the nucleus utilised?

How can electricity be used to transfer energy?

How is motion understood?

Options: How does physics inform contemporary issues and applications in society?

How do physicists investigate questions?

How do physicists explain motion in two dimensions?

This area of study takes Newton's laws off the straight line and into two dimensions. You apply them to linear and accelerated motion, to objects on inclined planes, and to uniform circular motion in both the horizontal plane (a car cornering, a banked track) and the vertical plane, where the net force changes relative to weight at the top and bottom of the circle. Projectile motion near Earth's surface is treated by separating independent horizontal and vertical components. The second half is the conservation toolkit: momentum and its conservation in collisions, impulse as the change in momentum and as the area under a force-time graph, and energy transformations between kinetic, elastic potential and gravitational potential energy, including elastic and inelastic collisions where kinetic energy is not conserved.

How do things move without contact?

Here you learn to describe action at a distance with field models, and to see what gravitational, electric and magnetic fields have in common and where they differ. You draw and interpret field patterns, apply the inverse square law to the field around a point charge or point mass, and superimpose the fields of two charges vectorially to find the net field, including the point where it cancels. Charged particles are then set moving through fields: accelerated between charged plates in a uniform electric field, and forced into circular paths in a magnetic field. The same physics explains the force on a current-carrying conductor, the operation of DC motors and particle accelerators, and satellites held in orbit by gravity, where the gravitational force supplies the centripetal acceleration.

How are fields used in electricity generation?

This area of study connects the field models to the electricity supply. You start with electromagnetic induction: magnetic flux through a coil, Faraday's law linking induced EMF to the rate of change of that flux, and Lenz's law fixing the direction of the induced current so that it opposes the change producing it. From there you work through the AC generator — how flux through a rotating coil varies, where in the rotation the EMF peaks, and how a commutator changes the output. You then handle alternating voltage and current quantitatively using peak and RMS values, compare AC and DC supplies delivering the same power, and finish with transformers and the transmission problem: stepping voltage up to cut the current, reducing power lost as heat in the transmission lines, then stepping it back down for use.

How has understanding about the physical world changed?

This area of study follows two ideas that broke classical physics. The first is the nature of light and matter: interference and diffraction establish light as a wave, then the photoelectric effect and atomic spectra force quantisation, with photon energy set by frequency and the work function setting the threshold. De Broglie's wavelength then runs the argument backwards, since electrons diffract like X-rays of similar wavelength, giving wave-particle duality. The second is special relativity: Einstein's two postulates, what counts as an inertial frame, and the consequences when the speed of light is the same for all observers — time dilation, length contraction measured in the frame that sees the object move, and mass-energy equivalence. Michelson-Morley and the muon are the standard pieces of supporting evidence.

How is scientific inquiry used to investigate fields, motion or light?

This is the practical investigation area of study, and it is examinable in its own right rather than being a report of your own experiment. You need to be fluent with the design of an investigation: identifying independent, dependent and controlled variables, choosing a method and equipment that actually isolate the relationship being tested, and recognising the difference between systematic error, which shifts every reading in one direction, and random error, which scatters them. You also need the analysis skills: plotting data with uncertainty bars, drawing a line of best fit, reading a gradient and an intercept and interpreting what each represents physically, linearising a relationship so a curved data set becomes a straight line, and evaluating accuracy, precision and the limitations of a method. Scientific poster conventions for communicating findings are part of the study design.