# An oscillator is producing a FM wave of frequency 1KHz with a variation of 5KHz.What is modulating index.

$\begin{array}{1 1}(a)\;0.5\\(b)\;5.0\\(c)\;0.2\\(d)\;2.0\end{array}$

Modulating index=$\large\frac{\text{frequency variation }}{\text{modulating frequency}}$
$\Rightarrow \large\frac{5KHz}{1KHz}$
$\Rightarrow 5$
Hence (b) is the correct option.
answered Mar 17, 2014