Question

a dolphin emits ultrasound of 100kHz and uses the timings of reflection to determine the position of objects in the water. What is the wavelengths of this ultrasound? Note the speed of sound in water is 1480m/s.

Answer 1

Wavelength = (speed) / (frequency)

= (1,480 m/s) / (100,000 /s)

= 0.0148 meter

= 1.48 centimeter

= 14.8 millimeters

Answer 2

The wavelength is 1.48 × 10⁻² m.

Step-by-step explanation:

Given data

• Frequency (f): 100 kHz = 100 × 10³ Hz = 100 × 10³ s⁻¹

• Speed (v): 1480 m/s

• Wavelength (λ): to be determined

We can find the wavelength of a mechanical wave using the following expression.

v = λ . f

λ = v/f = (1480 m/s) / 100 × 10³ s⁻¹ = 1.48 × 10⁻² m

The wavelength is 1.48 × 10⁻² m.