Frequency is the occurrence of an repeating event at a unit time. So, it is inversely proportional to time period. The other related term of frequency is period, which is the duration of one cycle. Mathematically, it can be represented as,

$f$ = $\frac{1}{T}$

where,

f is the frequency in Hz,

T is the period of time in sec.

$f$ = $\frac{1}{T}$

where,

f is the frequency in Hz,

T is the period of time in sec.

Step 2: Substitute these values in the given formula below,

$f$ = $\frac{1}{T}$

and calculate the desired parameter.

Given below are some of the problems based on frequency.

### Solved Examples

**Question 1:**Simran makes back and forth motion in a swing in 3.2 sec. What is the frequency?

**Solution:**

Step 1: Given :

T = 3.2 sec

f = ?

Step 2: Frequency, $f$ = $\frac{1}{T}$

$f$ = $\frac{1}{3.2}$

f = 0.31 Hz

Therefore, the frequency is 0.31 Hz.

**Question 2:**At what period does the sound wave is produced by turning fork of 440 Hz?

**Solution:**

Step 1: Given :

f = 440 Hz

T = ?

Step 2: Frequency, $f$ = $\frac{1}{T}$

440 = $\frac{1}{T}$

$T$ = $\frac{1}{440 Hz}$

T = 0.00227 s

Therefore, turning fork took 0.00227 s to produce the sound wave.