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Index of refraction and speed of light.

  • Thread starter jakey
  • Start date
  • #1
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Oh btw, this is not a homework question!!! just got it somewhere.
Light travels in a medium of n=1.2 at c1. what is its speed in a medium of n=1.6?

a)1.3c1
b)0.67c1
c)2c1
d)1.7c1
e)0.55c1

my solution:
using n=c/v, 1.2 = c/c1. also, 1.6=c/c2. c2= c/1.6. but c=1.2c1

So, c2=(1.2/1.6) c1=0.75c1. but it isnt in the choices. any help? thanks

also, do you know where i can find review materials for a-level physics (this is like UK based)? im preparing for university entrance exams. thanks!:>
 

Answers and Replies

  • #2
CompuChip
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Your reasoning is correct, the answer should be 0.75 c1.
Are you sure you copied all the numbers correctly?
 
  • #3
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Your reasoning is correct, the answer should be 0.75 c1.
Are you sure you copied all the numbers correctly?
i'm so sure that's why i'm so confused. however, 1.6/1.2=1.3 and its in the choices.
 
  • #4
CompuChip
Science Advisor
Homework Helper
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That's why I asked you to check the question.. if you'd interchange the 1.2 and 1.6, then the answer is there.
 

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