Question

A coil of inductance $0.4mH$ is connected to a capacitor of capacitance $400pF$ . To what wavelength, is this circuit tuned?

• A. $500m$
• B. $1507.2m$
• C. $753.6m$
• D. $376.8m$

Answer 1

Answer: (C)

$753.6m$

Resonance frequency is given as,

$f=\frac{1}{2\pi \sqrt[]{LC}}$

$f=\frac{1}{2\times 3.14\sqrt{\left(0.4\times {10}^{-3}\times 400\times {10}^{-12}\right)}}$

$=\frac{1}{6.28\times 4\times {10}^{-7}}$

$=\frac{{10}^7}{6.28\times 4}$

$=3.98\times {10}^{5}Hz$

Thus wavelength is given by,

$\lambda =\frac{c}{f}$

$=\frac{3\times {10}^8}{3.98\times {10}^5}$

$=753.7m$