What is the resonant frequency of a series RLC circuit, if R is 47 ohms, L is 3 microhenrys and C is 40 picofarads?

You can find the resonant frequency using the formula f = 1 / (2π√(LC)). Remember that resonance occurs when inductive reactance equals capacitive reactance, a point completely independent of the 47 ohms of resistance. Convert the components to standard units: L = 3 microhenrys (3 × 10^-6 H) and C = 40 picofarads (40 × 10^-12 F). Multiplying these together gives 1.2 × 10^-16. The square root of this is about 1.095 × 10^-8. Multiply this result by 2π to get the full denominator, which is approximately 6.883 × 10^-8. Dividing 1 by this value results in 14,528,000 Hz, which is 14.5 MHz. The kHz options trick students who lose track of their decimal places.