Units and conversions
Unit errors are the biggest single source of lost marks:
- Leaving the unit off a final answer, even when the number is correct.
- Not converting to SI before calculating, such as leaving mass in grams or length in centimetres.
- Forgetting to label graph axes with a unit.
Fix them by converting everything to SI at the start and treating the unit as part of the answer, never optional.
Working and rounding
Jumping straight to an answer throws away method marks. Always write the formula, substitution and unit. Rounding partway through the working introduces error, so keep extra digits and round only the final answer to a sensible number of significant figures.
Answering the wrong question
Many explanation marks are lost by not matching the command word. Describing when the question says explain, or giving one side of a comparison, loses marks even when the physics is correct. Underline the command word and answer the depth the marks ask for.
Definitions and diagrams
Vague definitions and unlabelled diagrams are quiet mark-losers. Learn the precise wording of key definitions, and label forces, rays, fields and readings on every diagram. In ray diagrams, remember to show the direction of light with arrows.
Find your own repeat mistakes
The fastest improvement comes from knowing which of these you make most. Keep an error log as you mark past papers, writing down each mistake and its correction. Patterns appear quickly, and a short one-to-one review of your scripts can surface habits you cannot see yourself.