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A charged 30 μF capacitor is connected to a 27 mH inductor. What is the angular frequency of free oscillations of the circuit?

Asked in GUJCET 2026 · Frequency and current in LC

Answer: (3) 1100 (rad)/s

Step-by-step solution

Given: C=30 μF=3×10⁻⁵ F and L=27 mH=2.7×10⁻² H; there is no resistance, so the oscillations are free.

Idea: the charged capacitor drives current into the inductor and the energy shuttles between the electric and the magnetic field at ω=1/(√LC).

LC=2.7×10⁻²×3×10⁻⁵=8.1×10⁻⁷ s².

√LC=9×10⁻⁴ s.

ω=1/(9×10⁻⁴)=1111 rad s⁻¹, which to two significant figures is the printed 1100 rad s⁻¹.

Why the other options are wrong

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