MCQ
Two tuning forks $A$ and $B$ vibrating simultaneously produce $5$ beats. Frequency of $B$ is $512.$ It is seen that if one arm of $A$ is filed, then the number of beats increases. Frequency of $A$ will be
- A$502$
- B$507$
- ✓$517$
- D$522$
✓
Answer
Correct option: C.
$517$
c
(c) After filling frequency increases, so ${n_A}$ decreases ($\downarrow$). Also it is given that beat frequency increases (i.e., $x \uparrow$)
(c) After filling frequency increases, so ${n_A}$ decreases ($\downarrow$). Also it is given that beat frequency increases (i.e., $x \uparrow$)
Hence $ n_A\downarrow -n_B = x\uparrow$ ... $(i)$ $\rightarrow$ Correct
$n_B -n_A\uparrow = x\uparrow$ ... $(ii)$ $\rightarrow$ Wrong
==> $n_A = n_B + x = 512 + 5 = 517 Hz.$
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