Two tuning forks $A\,\, \& \,\,B$ produce notes of frequencies $256 Hz \,\,\& \,\,262 Hz$ respectively. An unknown note sounded at the same time as $A$ produces beats . When the same note is sounded with $B$, beat frequency is twice as large . The unknown frequency could be ... $Hz$
A$268$
B$260$
C$250$
D$242$
Medium
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C$250$
c $|262-f|=|256-f| \times 2$
$\Rightarrow(262-f)=\pm(256-f) \times 2$
$\Rightarrow f=250,258 H z$
Unknown frequency can no be greater than $262 Hz$ because no. of beats heard with $262 \mathrm{Hz}$ is more then the no. beats heard with $256 \mathrm{Hz}$
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