Speed of light

[Primarygun]

When light passes a medium, it's speed decreases.

Is the acceleration of light decreased?

[Thales]

Light has no acceleration/deceleration because the speed of light is constant. the illusion of its speed changing in differing medium is to do with phase velocity. Do a quick google for futher information.

[Primarygun]

What's the keywords? Speed isn't slowed down when we look at it outside?

[pulkit]

Phase velocity AND wave velocity

[5614]

light can be slowed down in more dense materials:

 

http://news.bbc.co.uk/1/hi/sci/tech/1124540.stm

 

i'got a better link at home, but i can't access it now, i'll post it here later.

[5614]

heres the site:

 

http://www.newscientist.com/news/news.jsp?id=ns9999340

 

its also a more reliable source for scientific data than the BBC

[swansont]

light can be slowed down in more dense materials

 

Note that that was done in a dilute vapor - hardly a physically dense material. It's optically thick because the light is on resonance.

[Primarygun]

Thanks.I understand it now.Really appreciate everyone