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8.Electromagnetic waves
easy
If $E$ and $B$ denote electric and magnetic fields respectively, which of the following is dimensionless
A
$\sqrt {{\mu _0}{\varepsilon _0}} \frac{E}{B}$
B
$ {{\mu _0}{\varepsilon _0}} \frac{E}{B}$
C
${\mu _0}{\varepsilon _0}{\left( {\frac{B}{E}} \right)^2}$
D
$\frac{E}{{{\varepsilon _0}}}\frac{{{\mu _0}}}{B}$
Solution
Speed of light, $c=\frac{1}{\sqrt{\mu_{0} \varepsilon_{0}}}$
Also, $\frac{E}{B}=c$
Therefore, $\sqrt{\mu_{0} \varepsilon_{0}} \frac{E}{B}$ is dimensionless.
Standard 12
Physics
