Chapter 24 - Alternating-Current Circuits - Problems and Conceptual Exercises - Page 872: 102

$3740Hz$

We know that $f_{\circ}=\frac{1}{2\pi \sqrt{LC}}=\frac{1}{2\pi \sqrt{(2.08\times 10^{-6})(1.50\times 10^{-12})}}$ $f_{\circ}=90.10374\times 10^6Hz$ Now $f_{beat}=|f_{\circ}x-f_{\circ}|$ We plug in the known values to obtain: $f_{beat}=|90.1000\times 10^6-90.10374\times 10^6|=3740Hz$