The dimensional formula for \( \displaystyle\frac{1}{(\mu\varepsilon)} \) is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( [L^{2}T^{-2}] \)
The speed of an electromagnetic wave in a medium is \( v = 1/\sqrt{\mu\varepsilon} \) (in vacuum, \( c = 1/\sqrt{\mu_{0}\varepsilon_{0}} \)). So \( 1/(\mu\varepsilon) \) is the square of a speed:
\( \displaystyle \frac{1}{\mu\varepsilon} = v^{2} \)
\( [v^{2}] = [LT^{-1}]^{2} = [L^{2}T^{-2}] \)