A LevelPhysicsOCRRevision Notes5. Newtonian World & AstrophysicsCircular MotionTime period & Frequency

Time period & Frequency (OCR A Level Physics): Revision Note

Exam code: H556

Written by: Ann Howell

Reviewed by: Caroline Carroll

Updated on 2 July 2026

Period & Frequency in Circular Motion

Frequency, f, is defined as:
The number of complete oscillations per unit time
It is measured in Hertz (Hz) and is defined by the equation

Time period, T, is defined as:
The time taken for one complete oscillation, in seconds
One complete oscillation is defined as:
The time taken for the oscillator to pass the equilibrium from one side and back again fully from the other side
If a circle has a radius r, then the distance through which an object moves as it completes one rotation is equal to the circumference of the circle = 2πr
The speed of an object moving in a circle is therefore equal to:

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Author: Ann Howell

Expertise: Physics Content Creator

Ann obtained her Maths and Physics degree from the University of Bath before completing her PGCE in Science and Maths teaching. She spent ten years teaching Maths and Physics to wonderful students from all around the world whilst living in China, Ethiopia and Nepal. Now based in beautiful Devon she is thrilled to be creating awesome Physics resources to make Physics more accessible and understandable for all students, no matter their schooling or background.

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.