One might think that light having weight is awkward, but it does exert weight.
Thinking light as photons (thereby taking the advantage of its dual nature), we know that photons are mass-less.
Yes; their rest mass is zero. But when they move (of course, at the speed c), they have momentum (E=mc2 and hence, m=Ec2). Photons cannot stay at rest, because that violates relativity.
[The actual relativistic equation is E2=m2c4+p2c2]
Maxwell wrote:
So, when the light is incident on an object, that object weighs a bit more, owing to the 'pressure' it exerted.
P.S.: The city of Chicago weighs 140 kg (300 lbs) more in a sunny day compared to a normal one!
Thinking light as photons (thereby taking the advantage of its dual nature), we know that photons are mass-less.
Yes; their rest mass is zero. But when they move (of course, at the speed c), they have momentum (E=mc2 and hence, m=Ec2). Photons cannot stay at rest, because that violates relativity.
[The actual relativistic equation is E2=m2c4+p2c2]
Maxwell wrote:
In a medium in which waves are propagated there is a pressure in the direction normal to the wave, and numerically equal to the energy contained in unit of volume.Hence, the pressure exerted by light can be calculated (force exerted over unit area; and this force can be called as the 'weight exerted by' light!)
So, when the light is incident on an object, that object weighs a bit more, owing to the 'pressure' it exerted.
P.S.: The city of Chicago weighs 140 kg (300 lbs) more in a sunny day compared to a normal one!
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