Question

a source of wave produced 40 crest and 40 troughs in 0.4 second .what is the frequency of the wave

Answer 1

1c+1t=1 wave
40c+40t=40wave in 0.4sec
in1sec.= 40*1/0.4=100
frequency =100/1= 100Hz

Answer 2

Aɴꜱᴡᴇʀ

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

_________________

Gɪᴠᴇɴ

An object vibrates 40 times in 0.4 seconds.

_________________

ᴛᴏ ꜰɪɴᴅ

The frequency of the wave.

_________________

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.

_________________

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