Question

a source of wave produces 40 crests and 40 troughs in 0.4 sec . find the frequency of the wave

Answer 1

Frequency = No. of oscillation / Time taken

= 40 / 0.4

= 100 Hz

Answer 2

Aɴꜱᴡᴇʀ

$\large \sf \orange{100hz}$

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Gɪᴠᴇɴ

An object vibrates 40 times in 0.4 seconds.

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ᴛᴏ ꜰɪɴᴅ

The frequency of the wave.

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Sᴛᴇᴘꜱ

$\begin{lgathered}\dashrightarrow\sf{Frequency=\dfrac{Number\:of\:oscillations}{Time\:taken} }\\\\\\\\\leadsto\sf{Frequency=\dfrac{40\times 10}{0.4\times 10} }\\\\\\\\\leadsto\sf{Frequency=\cancel{\dfrac{400}{4} }}\\\\\\\\\mapsto\sf{\pink{Frequency=100\:Hz}}\end{lgathered}$

The frequency of the wave is 100 hertz (Hz).

Additional information:-

The number of vibration in a second is called frequency.

Its SI unit is Hertz.

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$\huge{\mathfrak{\purple{hope\; it \;helps}}}$