Movement of Photons

[Jarif Mahbub Srabon]

Do the photons move slowly in the solid medium?

[sowmitra]

Photons move through vacuum at the speed of 300,000 km/sec. This is the highest speed of photons(or light). In a definite medium, the speed of photons is constant, but it changes from one medium to another. And yes, photons do travel slower in solid media than they would do in vacuum. But, photons can only pass through transparent solid substances; they are obstructed by opaque bodies.
No body or radiation can travel faster than light in vacuum. But, some radiations can travel faster than light in other media such as, glass or water, because photons travel slower through these media. In such a case, a special type of light or radiation, known as "Cherenkov Light" or "Cherenkov Radiation", is produced. To learn more, check Wiki.
http://en.wikipedia.org/wiki/Cherenkov_radiation
And, here's a nice video which might help you understand the topic better:
http://www.youtube.com/watch?v=Do1lm9Ie ... g-logo-xit

[Jarif Mahbub Srabon]

Thanks, Sowmitra Vai