so, if u have... say a pice of paper in space (pretending space is a perfect vacum) and shone a torch at it, and light hit it and refelected off it, would it move the paper, also im not talking about photons, im taking about the EM wave, any thoughts ???
2006-12-07 03:19:42 · 3 answers · asked by rustawill 1 in Science & Mathematics ➔ Physics
And if for argument sake it would move the paper then energy from the light has been lost and it would eventually run out?
2006-12-07 03:20:44 · update #1
EM waves are photons depending on how you measure them. A piece of paper will not work. It has to be a very reflective surface like a mirror or a foil. The photon does not bounce off the mirror. The mirror absorbs the photon and then re-radiates another. The new photon moves away with a with a momentum and the mirror has a momentum in the opposite direction. Because of a Doppler shift caused by motion of the mirror, the photon frequency is lowered. The change in frequency can be equated to the momentum imparted to the mirror or reflective sail
2006-12-07 03:31:25 · answer #1 · answered by Gene 7 · 0⤊ 0⤋
A good demonstration of the force that is exerted, are the small glass spheres, usually a few inches in diameter, containing a vacuum, and typically 4 small square paddles mounted on a frame so that they are free to rotate.
When the sun hits the small squares (white on one side, black on the other) the paddles rotate. When the light is removed, the rotation stops. The only force acting on this, light.
These are typically found in stores that sell science toys for children.
2006-12-07 04:38:49 · answer #2 · answered by Xander 2 · 0⤊ 0⤋
Yes it's called radiation pressure.
It's the fundamental concept that makes solar sails work.
2006-12-07 03:28:59 · answer #3 · answered by cw 3 · 0⤊ 0⤋