IGCSE Physics Formulas Explained: The Essential Guide

A clear breakdown of the most important IGCSE Physics formulas, what they mean, and how to apply them confidently in exams.

Mechanics and Motion Formulas

The mechanics formulas form the backbone of IGCSE Physics. Speed = distance / time is the starting point, but the key equations are the SUVAT formulas for uniformly accelerated motion: v = u + at, s = ut + ½at², and v² = u² + 2as. For every calculation, write down the known variables first, identify the unknown, then select the formula that connects them. Newton's second law F = ma links force, mass, and acceleration and appears in almost every paper — always check your units are in SI (newtons, kilograms, metres per second squared).

Electricity and Energy Formulas

Electricity questions carry heavy marks on IGCSE Physics papers. The three forms of Ohm's law — V = IR, I = V/R, R = V/I — must become second nature. For power calculations, use P = IV, P = I²R, or P = V²/R depending on which variables you are given. Energy transferred is E = Pt (power times time) or E = QV (charge times voltage). In circuit problems, remember that in series circuits current is the same everywhere and voltages add up, while in parallel circuits voltage is the same across each branch and currents add up. Always draw a clear circuit diagram before attempting calculations.

Waves, Thermal Physics, and Nuclear Formulas

The wave equation v = fλ (wave speed = frequency times wavelength) is fundamental and applies to sound, light, and water waves alike. For thermal physics, the specific heat capacity formula E = mcΔT calculates energy needed to change a substance's temperature, while E = mL handles changes of state. In nuclear physics, understand that mass number and atomic number are conserved in every equation — this is how you balance nuclear decay equations. These topics are often tested together in multi-step problems, so practise linking formulas across different areas of the syllabus.

Understanding the formulas is only half the battle — applying them correctly under exam conditions is what separates A* students from the rest. If you want to build confidence with IGCSE Physics calculations, book a free session to practise with real exam questions.