The Physics of Waves: Light Waves, Sound Waves and Ultrasound

Blood flow is fastest as the left ventricle contracts. The velocity of blood flow decreases between contractions. In fact flow is momentarily retrograde as the aortic valve fills and closes. Then forward flow continues as the elastic artery walls recoil from being distended. The other answers are nonsense.

As a wave passes through a medium, the particles of the medium are shifted (displaced) from the position occupied before they were disturbed by the wave. The amplitude of the wave is the maximum displacement.

Ultrasound has frequencies greater than 20 kHz. In medical applications, the frequencies used are greater than 1 MHz.

v = fλ so f = v/λ = 3 × 10⁸ m/s ÷ 600 nm = 3 × 10⁸ m/s ÷ 600 × 10−⁹ m = 1800 × 10⁸− −⁹ = 1800 × 10−¹⁷ = 1.8 × 10¹⁴ Hz.

Wavelength is the shortest distance between two points that are displaying the same displacement.

A large difference in acoustic impedance will cause a large reflection. Impedance depends on both speed of sound in the medium and the density of the medium.

Concave lens will cause light rays to diverge. So it can be used to correct short-sightedness as they shift the focal point further away from the eye’s lens.

Which combination of frequency and wavelength will give the speed 3 × 10⁸ m/s? v = fλ = 5 × 10¹⁴ Hz × 6 × 10−⁷ m = 30 × 10^14–7 = 30 × 10⁷ = 3 × 10⁸

Frequency of an EM wave does not change as it travels through different media, while the other three quantities do.

This is the classic definition of a wave. Choices B and D are also true statements.