Question

An $ L-C $ resonant circuit contains a 400 pF capacitor and a $ 100\,\mu H $ inductor. It is set into oscillation coupled to an antenna. The wavelength of the radiated electromagnetic waves is

• A. 377 mm
• B. 377 m
• C. 377cm
• D. 3.77cm

Answer 1

Answer: (B)

Frequency of radiated electromagnetic waves $ v=\frac{1}{2\pi \sqrt{LC}} $ $ =\frac{1}{2\pi \sqrt{100\times {{10}^{-6}}\times 400\times {{10}^{-12}}}}=\frac{{{10}^{7}}}{4\pi }Hz $ $ \therefore $ Wavelength, $ \lambda =\frac{c}{v} $ $ =\frac{3\times {{10}^{8}}}{{{10}^{7}}/4\pi } $ $ =120\pi $ $ \simeq 377\,m $