Question

An object vibrates 40 times in 0.4 seconds. Find the frequency of the wave. 10000Hz
10Hz
100Hz
1000HZ

Answer 1

AnswEr :

100 Hz.

$\bf{\purple{\underline{\underline{\bf{Given\::}}}}}$

An object vibrates 40 times in 0.4 seconds.

$\bf{\purple{\underline{\underline{\bf{To\:find\::}}}}}$

The frequency of the wave.

$\bf{\purple{\underline{\underline{\bf{Explanation\::}}}}}$

$\bf{We\:have}\begin{cases}\sf{Vibrates\:object\:=40\:times}\\ \sf{Time\:=0.4\:seconds}\end{cases}}$

A/q

$\hookrightarrow\sf{Frequency=\dfrac{Number\:of\:oscillations}{Time\:taken} }\\\\\\\\\hookrightarrow\sf{Frequency=\dfrac{40\times 10}{0.4\times 10} }\\\\\\\\\hookrightarrow\sf{Frequency=\cancel{\dfrac{400}{4} }}\\\\\\\\\hookrightarrow\sf{\purple{Frequency=100\:Hz}}$

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

$\bf{\underline{\underline{\tt{Frequency\::}}}}}}$

The number of vibration in a second is called frequency.

Its unit is Hertz.

Answer 2

Answer:

Explanation:

The given source produces 40 crests and 40 troughs, hence it produces 40 wave cycles in the given interval 0.4 seconds.  

Therefore, number of wave cycles produced in 1 second =  

0.4

40×1

​  

=100

We know that the number of wave cycles produced in one second is equal to the frequency.

Hence, the frequency of the wave is 100 Hz