What is the resonant frequency of a series RLC circuit, if R is 47 ohms, L is 8 microhenrys and C is 7 picofarads?

To find the resonant frequency, use the standard resonance formula: f = 1 / (2 * π * √(L * C)). The 47 ohms of resistance is a distractor; resistance does not shift the resonant frequency in a standard series RLC circuit. Convert the given values to their standard units: 8 microhenrys is 8 × 10^-6 H, and 7 picofarads is 7 × 10^-12 F. Multiplying these together gives 56 × 10^-18. Taking the square root and multiplying by 2π, then taking the reciprocal, gives approximately 21.27 × 10^6 Hz, or 21.3 MHz. Misplacing a decimal point in your scientific calculator is the primary reason for choosing the incorrect 2.13 MHz or kHz distractors.