A student assembles a series RLC circuit with a resistor of resistance and a…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A student assembles a series RLC circuit with a resistor of resistance R=20.0±0.5Ω and a capacitor of capacitance C=0.050μF (negligible error). Using a variable–frequency a.c. source of fixed r.m.s. voltage 8.0 V, the maximum current is observed at a frequency of f0=3.20±0.05kHz.
(i) Calculate the inductance of the coil and the percentage uncertainty in its value arising from the uncertainty in the measured resonant frequency.
(ii) Determine the r.m.s. current at resonance and the percentage uncertainty in this current.
(iii) When the frequency is increased to 3.50 kHz the r.m.s. current falls to 0.30 A. Using your component values, show quantitatively whether the circuit is predominantly inductive or capacitive at 3.50 kHz.