Question

light and sound frequencies Wave Frequency (hz) A note on guitar 440 C note on guitar 256 red laser light 4 x 1014 violet light beam 8 x 1014 Based on the table and your knowledge of waves, what can you conclude about the wavelength of mechanical waves compared to electromagnetic waves? A) Mechanical waves have greater amplitude. B) Mechanical waves tend to have longer wavelengths. C) Mechanical waves tend to have shorter wavelengths. D) Mechanical waves travel faster than electromagnetic waves.

Answer 1

B)Mechanical waves tend to have longer wavelengths

Sound is a mechanical wave. Wavelength and frequency are inversely related. So, Mechanical waves tend to have longer wavelengths.

Answer 2

Answer:

B) Mechanical waves tend to have longer wavelengths.

Explanation:

As we know the relation between frequency and wavelength is given as

$wavelength = \frac{speed}{frequency}$

now we know that

speed of electromagnetic waves are

$c = 3 \times 10^8 m/s$

now we have wavelength of violet light given as

$\lambda = \frac{3 \times 10^8}{8 \times 10^{14}}$

$\lambda = 3.75 \times 10^{-7} m$

now similarly if we will find the wavelength of red light then it is

$\lambda = \frac{3 \times 10^8}{4 \times 10^{14}}$

$\lambda = 7.5 \times 10^{-7} m$

now if we use the same formula to find the wavelength of sound then it is

wavelength of note A on guitar

$\lambda = \frac{340}{440} = 0.77 m$

wavelength of note C on guitar

$\lambda = \frac{340}{256} = 1.33 m$

so by above all calculations we can see that frequency of electromagnetic waves are much larger than the frequency of mechanical waves due to which wavelength of mechanical waves is larger than the wavelength os electromagnetic waves.