Question

1. + 2.77/5.55 points Previous Answers KatzPSE1 34.P.053. My Notes + Ask Your Teacher Optical tweezers use light from a laser to move single atoms and molecules around. Suppose the intensity of light from the tweezers is 1000 W/m2, the same as the intensity of sunlight at the surface of the Earth. (a) What is the pressure on an atom if light from the tweezers is totally absorbed? 3.33e-6 ✓ Pa (b) If this pressure were exerted on a hydrogen atom, what would be its acceleration? (The mass of a hydrogen atom is 1.67 x 10-27 kg. Assume the cross- sectional area of the laser beam is 6.65 x 10-29 m2.). m/s2

Answer 1

C46 When light falls (at normal incidence) ou a perfect absorber, it delivers it momentum to the surface. In a time who st, the het momentum transfer Ap> <g>Xe 4t)x A Where <9> - average momentum density of Ite. the light's EM field. A Cat = Nolume created in at time, Pressure - Force - rateof change of inomenten area Area. Hences ☆ P = <g>.c Now, Kg) = 1/62] SO , Pressure (P) = I = Intensily Velocity of light P= Pascal. P = 0 3.33x10-6 Pascal 38108 in to find the acceleration, we need to know force. Ne know, Pressure = Force Force = Pressure xorea) area.

force a 3.38x 16 x G. 65x10 29 News Since, tweezers used to move bully Single atoms and molecules; so, area of the atom in nearly equals to cross-sectional aso a of the lasen beam. F = 2,214 X 1034 Newson. Newton's law says, Fama > a= fm = 2121481039 1.67*10-27 My a= 1.338 10-7 m/s.