What are the dimensions of the product LC, where L is inductance and C is capacitance?
Options
A.
Option A
[T]
B.
Option B
[T−1]
C.
Option C is correct
[T2]
(Correct)
D.
Option D
[M0L0T0]
Explanation
In an LC circuit, the resonant angular frequency ω is given by ω=LC1. The dimension of angular frequency ω is [T−1] (since ω=2π/T, where T is period).
From the formula, we have [LC]1=[T−1].
This implies [LC]=[T].
Squaring both sides gives [LC]=[T2].
Alternatively, one can find the dimensions of L and C separately:
Inductance L: From Faraday's law, V=LdtdI, so [L]=[I][T−1][V]. Since V=W/Q=W/(IT), [V]=[AT][ML2T−2]=[ML2T−3A−1]. Therefore, [L]=[A][T−1][ML2T−3A−1]=[ML2T−2A−2].
Capacitance C: From Q=CV, so C=Q/V. Since Q=IT, [C]=[ML2T−3A−1][AT]=[M−1L−2T4A2].
Multiplying [L] and [C]:
[LC]=[ML2T−2A−2]×[M−1L−2T4A2]=[M1−1L2−2T−2+4A−2+2]=[M0L0T2A0]=[T2].