Question

A source produces 20 crests and 20 troughs in 4 seconds. The second crest is 3 cm away from the first crest.Calculate :

i. Wavelength [ Ans : 3 ×
`{10}^( - 2)` m ]
ii. Frequency [ Ans : 5 Hz ]
iii. Wave speed [ Ans : 1.5 ×
`{10}^( - 1) \tt{ {ms}^( - 1)}` ]

Show your workings !
*Irrelevant / Random answers will be reported!

Answer 1

Solution given:

No of waves[N] =20crests & 20 troughs

=20waves

Time[T]=4seconds

distance[d]=3cm=0.03m

Now

Wave length=3cm=3 ×
`{10}^( - 2)m`

Frequency=
`(No of waves)/(time)`

=
`(20)/(4)`=5Hertz

and

Wave speed:wave length×frequency=3 ×
`{10}^( - 2)m`×5=1.5 ×
`{10}^( - 1) \tt{ {ms}^( - 1)}`.