Question

2. Electromagnetic waves can exert force on objects because they carry momentum. A common laser pointer has a power rating of P and a cross-sectional radius of r. a. What is the intensity, I, of the laser pointer? For simplicity, we say that the energy distribution is uniform. b. What is the radiation pressure, p, if the laser pointer is aimed directly at a perfectly reflecting surface? c. What is the force, F, the laser beam exerts on a perfectly reflecting object?

Answer 1

2. a) Intensity I = Power & Area P X IN Para Watt/m2 b) Radiation direty at pressure p, if lases is aimed perfectly reflecting surface, P Intensity c (speed of light) I PI Pascals Radiation pressure P C) fonce f excested by laser beam on a perfletly reflecting Schject, Force f = Radiation pressure Area X p Х ? p P (2) F = ܕ ܐpn Newton C