Question

A sound wave has frequency of 2 kHz and wavelength 35 cm. how long will it take to travel 1.5km?

Answer 1

The speed of the sound wave will be

v = wavelength x frequency

or

v = λ x f

here,

λ = 35cm = 0.35m

f = 2kHz = 2000 Hz

thus,

v = 0.35 x 2000 = 700 m/s

now, time taken by it to travel 1.5km (=1500 m) will be

t = velocity / distance = 700/1500

thus,

t = 0.467 second

Answer 2

Answer:

It will take 2.14 second to travel 1.5 km.

Explanation:

Given,

Frequency = f = 2kHz = 2000 Hz

Wavelength = λ = 35 cm = 35 / 100 m

To find: How long will it take to travel 1.5 km

Solution:

Concept: Wave speed is defined as the product of wavelength and frequency.

i.e v = λf

here, λ = 35/100 m and f = 2000 Hz

Substituting the values,

v = 35/100* 2000 = 700 m /s

So, Speed of sound wave is 700 m/s

Then, Time taken to travel the distance of 1.5 km = 1500 m will be:

Time taken = distance travelled / wave velocity

or, t = 1500 / 700 = 2.14 seconds

Therefore, it will take 2.14 second to travel 1.5 km.