Modern Physics 7 Question 31
32. A signal of $5 kHz$ frequency is amplitude modulated on a carrier wave of frequency $2 MHz$. The frequencies of the resultant signal is/are
(2015 Main)
(a) $2 MHz$ only
(b) $2005 kHz 2000 kHz$ and $1995 kHz$
(c) $2005 kHz$ and $1995 kHz$
(d) $2000 kHz$ and $1995 kHz$
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Solution:
- $f _c=2 MHz=2000 kHz, f _m=5 kHz$
Resultant frequencies are,
$$ \begin{array}{r} f _c+f _m, f _c \text { and } f _c-f _m \\ \text { or, } 2005 kHz, 2000 kHz \text { and } 1995 kHz \end{array} $$