Free physics, mathematics and computer science notes for Punjab Board, Cambridge O Level and Cambridge A Level — written so the concept is clear before the formula appears, and illustrated with diagrams you can work with directly.
Every topic begins with what is actually happening, not with an equation to be memorised. Once the idea is clear, the formula becomes something you could reconstruct rather than something you have to recall — which is what holds up when a question is set in an unfamiliar form.
Concepts that depend on change carry a diagram you can adjust directly — a secant converging on a tangent, a sample rate falling until the waveform breaks down. The behaviour is shown rather than described.
Each topic presents the concept in written form, then as a diagram you can work with, then as questions. The questions explain not only the correct answer but why the most plausible wrong one is wrong, since that is usually where the misunderstanding sits.
Exam questions carry a real mark scheme, with marks shown on the line where they are earned. Chapter lists are checked against the syllabus the board actually publishes, so nothing here teaches content that left the paper years ago.
Chapter by chapter, matching the PCTB textbooks — Matric and Intermediate, SSC and HSSC, whichever name your school uses.
Mathematics D, Physics and Computer Science, organised by the numbered subtopics the examiner lists.
Mathematics, Physics and Computer Science at AS and A2. Being written now, so this track is still filling in.
STEMLinePK teaches STEM on YouTube. This site covers the same material in a form you can work through at your own pace — written topics, notes, interactive diagrams and questions with full mark schemes. The videos suit a first encounter with a topic; the written lessons suit revisiting the parts that are still unclear.
No account, no email, no locked chapters. Your progress is saved in your own browser and never sent anywhere — the privacy page says exactly what is stored. Corrections are welcome; a wrong sign in a worked example costs somebody marks.
Pick your board and your class, and the chapters will be the ones in your book.
Open the library