In which of the following materials is the velocity of light greatest?
A. Air
B. Water
C. Crown glass
D. Fused quartz
2006-10-11 23:22:30 · 18 answers · asked by djat20 2 in Science & Mathematics ➔ Physics
A. Air. Definitely.
Hey dude, dont get trip on this..
its simple and easy..
Speed of light depends on the refractive index of a medium ...
The larger the Ref. Indx. the Less The Velocity in it.
Air has ref index = 1 (approx.)
and the speed is just a bit (very bit less ) than that of vaccuum...
It is fastest in vaccuum..
Glass has ref index of 1.5
and water also has index more than air...
Got it dude... :-)
2006-10-11 23:44:34 · answer #1 · answered by Anurag 2 · 0⤊ 0⤋
Air is the medium listed above with the lowest refractive index, at 1.0008.
Water is at 1.33, glass is typically 1.5 or so and quartz is around 1.55.
Vacuum is 1.0, and the refractive index is the ratio of the speed of light between the two medium, therefore, the highest the refractive index, the slowest lights propagates.
So, your answer is A. Air.
(And for those who claim light travels at the same speed regardless of the medium, it is time they go back to school, or refrain from answering to things they know nothing about)
2006-10-11 23:33:36 · answer #2 · answered by Vincent G 7 · 0⤊ 0⤋
velocity is greatest in air, about 3*10^8 m/s. In water it is 2*10^8 m/s. The others are even lesser.
Strangely, it is opposite in the case of sound; it is fastest in solids, then liquids, then gases.
This is so because light is an electromagnetic wave, so does not require a medium for transmission. Water and solids are merely an obstruction.
But sound, being a mechanical wave, needs a medium, and solids provide the best.
2006-10-11 23:31:35 · answer #3 · answered by the_answerer 2 · 0⤊ 0⤋
The refractive index n of a medium is given by the formula n=co/c, where co is the speed of light in vacuum and c the speed of light in the medium in respect.
The n of air is a bit over 1 (actually it's 1.000293) similar to the refractive index of vacuum, so c~co.
The values of n for the other three materials are considerably larger than 1, so c
2006-10-12 08:33:56 · answer #4 · answered by fanis t 2 · 0⤊ 0⤋
Air
2006-10-11 23:29:55 · answer #5 · answered by Vanguard 3 · 0⤊ 0⤋
Light travels fastest through air because it has the lowest refractive index (slightly more than a pure vacuum). Materials with higher indices bend (refract) light more because light travels slower through the material.
2006-10-11 23:30:52 · answer #6 · answered by Kes 7 · 0⤊ 0⤋
Light travels fastest through air because it has the lowest refractive index (slightly more than a pure vacuum). Materials with higher indices bend (refract) light more because light travels slower through the material.
well so in air,light travels almost as fast as vacuum..that is 300000000 m/s..
2006-10-11 23:43:12 · answer #7 · answered by zero 3 · 0⤊ 0⤋
Air.
2006-10-11 23:24:36 · answer #8 · answered by Joe Cooker 3 · 0⤊ 0⤋
What you need to do is find out the Refractive Index of the four media. These are:
A. 1.0008
B. 1.330
C. 1.51
D. 1.434
The answer is therefore A followed by B, then D, then C.
2006-10-11 23:36:40 · answer #9 · answered by Stuart T 3 · 0⤊ 0⤋
Light travels at the speed of 186,272 miles a second no matter what the condition if it can be transfered.
2006-10-11 23:25:46 · answer #10 · answered by TMAC 5 · 0⤊ 0⤋