Question

A sound wave has a frequency 2 kHz of wave length 36 cm how long will it take to travel 1.5 km

Answer 1

GIVEN:

frequency( n) =2kHz= 2 x 1000 Hz= 2000Hz

[ 1kHz = 1000 Hz]

Wavelength(λ) = 36cm=36/100=0.36m

[ 1cm = 1/100 m]

Distance= 1.5km= 1.5x1000m = 1500 m

[1km = 1000 m]

Speed of sound(V)= frequency× wavelength

V =2000×0.36

V=720m/s

Speed=Distance/ time

Time= distance/ speed

Time = 1500/ 720

Time =2.08sec.

Hence, the time required to travel 1.5km is 2.08sec.

HOPE THIS WILL HELP You

Answer 2

☘️ Given :

• Frequency, v = 2 kHz = 2000 Hz
• Wavelength, λ = 35 cm = 0.35 m
• How long will it take to travel 1.5 km?

☘️ Formula we will use :

v of the wave = wavelength × frequency

☘️ Solution :

So, as we know that speed, v of the wave = wavelength × frequency

$\\ \large v \: = λ \: v \\ \\ \sf = 0.35 \: m \times 2000 \: Hz \\ \\ \sf = 700 \: m/s$

The time taken by the wave to travel a distance, d of 1.5 km is

$\\ \large\sf \:t \: = \: \dfrac{d}{v} \sf = \: \frac{1.5 \times 1000 \: m}{700 \: m \: s {}^{ - 1} } \sf = \frac{15}{7} \: s \\ \\ \large\sf = 2.1 \: s.$

Thus sound will take 2.1 s to travel distance of 1.5 km.