Question

what is the frequency of wave with time period 0.025 sec ?

Answer 1

Frequency = 1/time period
  
                  = 1/ 0.025
               
                  = 40Hz

Answer 2

Hey mate, your answer would be-

we know time period =1/frequency
therefore, frequency=1/time period
=1/0.025Hz
=1000/25Hz (on multiplying both of them by 1000 to remove points and ease it)
=40 Hz....
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HOPE IT HELPED YOU......... :-)