Units & Dimensions

JEE Main level, single correct, medium

73 of 149

Question 73 of 149

Dimension of 1μ0ϵ0\dfrac{1}{{\mu }_{0}{\epsilon }_{0}} should be equal to

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Answer: (C) L2T−2{L}^{2}{T}^{-2}

The speed of light can be written as
c=1μ0ϵ0...(1)c=\dfrac{1}{\sqrt{{\mu }_{0}{\epsilon }_{0}}}...\left(1\right)
Rearrange equation (1) to obtain the required quantity.

1μ0ϵ0=c2...(2)\dfrac{1}{{\mu }_{0}{\epsilon }_{0}}={c}^{2}...\left(2\right)
Use the method of dimensional analysis to obtain the dimension of the required quantity.

[1μ0ϵ0]=[LT−1]2=L2T−2\begin{matrix}\left[\dfrac{1}{{\mu }_{0}{\epsilon }_{0}}\right] & = & {\left[L{T}^{-1}\right]}^{2} \\ & = & {L}^{2}{T}^{-2}\end{matrix}

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