A second harmonic has to be generated in a string of length l str… - Vidyadip

MCQ

A second harmonic has to be generated in a string of length $l$ stretched between two rigid supports. The point where the string has to be plucked and touched are

✓
Plucked at $\frac{l}{4}$ and touch at $\frac{l}{2}$
B
Plucked at $\frac{l}{4}$ and touch at $\frac{{3l}}{4}$
C
Plucked at $\frac{l}{2}$ and touched at $\frac{l}{4}$
D
Plucked at $\frac{l}{2}$ and touched at $\frac{{3l}}{4}$

✓

Answer

Correct option: A.

Plucked at $\frac{l}{4}$ and touch at $\frac{l}{2}$

a
(a) Second harmonic means $2$ loops in a total length
Hence plucking distance from one end $ = \frac{l}{{2p}} = \frac{l}{{2 \times 2}} = \frac{l}{4}.$

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