Physics A-Level
Inverse-square law for a point source
What Inverse-square law for a point source means in Physics A-Level, as defined for OCR.
Definition of Inverse-square law for a point source
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Reference: OCR
For a point source radiating equally in all directions, the power spreads over a sphere of area 4πr², so I = P/(4πr²) and intensity falls with the square of distance.
Topics that use Inverse-square law for a point source
- Wave motion (OCR A-Level)
Related terms
- Amplitude
- Compressions and rarefactions
- Diffraction and gap-to-wavelength ratio
- Displacement
- Displacement–distance graph
- Frequency
- Frequency as a source-determined property
- Intensity
Using Inverse-square law for a point source in the exam
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