Optics Question 271
Question: Light is an electromagnetic wave. Its speed in vacuum is given by the expression
[CBSE PMT 1993; MP PMT 1994; RPMT 1999; MP PET 2001; Kerala PET 2001; AIIMS 2002]
Options:
A) $ \sqrt{{\mu _{o}}{\varepsilon _{o}}} $
B) $ \sqrt{\frac{{\mu _{o}}}{{\varepsilon _{o}}}} $
C) $ \sqrt{\frac{{\varepsilon _{o}}}{{\mu _{o}}}} $
D) $ \frac{1}{\sqrt{{\mu _{o}}{\varepsilon _{o}}}} $
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Answer:
Correct Answer: D
Solution:
$ {\mu _{0}}=4\pi \times {{10}^{-7}},{\varepsilon _{0}}=8.85\times {{10}^{-12}}\frac{N\text{-}m^{2}}{C^{2}} $
So $ c=\frac{1}{\sqrt{{\mu _{0}}{\varepsilon _{0}}}}=3\times 10^{8}\frac{meter}{sec}. $
