Pressure on Area Makes Force - Electromagnetic Waves and Radiation Step by Step

Radiation pressure acting over an area gives the total force on the surface, F = P * A, the push a sail or panel actually feels. This force ledger is exact only for stated pressure, area, surface orientation, and absorption assumptions. Real beams add nonuniform profiles, surface losses, alignment error, calibration, and measurement uncertainty.

Radiation pressure becomes force only after multiplying by illuminated area. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Pressure over area makes force

The illuminated area is checked before the force label is accepted.

F=pA_s=1\cdot 3=3\ \text{N}

Pressure alone is not force

The force label is separate from the pressure label.

A_s=3\ \text{m}^{2}