Question

A tuned amplifier circuit is used to generate a carrier frequency of $2\, MHz$ for the amplitude modulation. The value of $\sqrt{LC}$ is

• A. $\frac{1}{2 \pi \times 10^{6}}$
• B. $\frac{1}{2 \times 10^{6}}$
• C. $\frac{1}{3 \pi \times 10^{6}}$
• D. $\frac{1}{4 \pi \times 10^{6}}$

Answer 1

Answer: (D)

$\frac{1}{4 \pi \times 10^{6}}$

Answer 2

By transistor as an oscillator
$f=\frac{1}{2 \pi \sqrt{L C}}$
where $f=2\, MHz =2 \times 10^{6}\, Hz$ and $\sqrt{L C}=?$
$\Rightarrow \sqrt{L C}=\frac{1}{2 \pi f}$
$=\frac{1}{2 \pi \times 2 \times 10^{6}}=\frac{1}{4 \pi \times 10^{6}}$