Answer to Question #162253 in Optics for Yolande

Question

Which of the following statements are true regarding electromagnetic waves traveling through a vacuum? More than one statement may be correct.

A. All waves travel at 3.00 x 10^8 m/s

B. All waves have the same frequency

C. All waves have the same wavelength

D. The electric and magnetic fields associated with the waves are perpendicular to each other and to the direction of wave propagation.

Answer 1

The relationship between frequency, wavelength, and the speed of a wave is $\nuλ=v$ . In a vacuum, all electromagnetic waves travel at the same speed: v=c.

Electromagnetic waves, consisting of oscillating electric and magnetic fields, are transverse waves.

$-$ All waves travel at $3.00 *10^8 m/s.$

$-$ The electric and magnetic fields associated with the waves are perpendicular to each other and to the direction of wave propagation.

Explanation:

Let's analyze each statement:

- All waves have the same wavelength. --> FALSE. Electromagnetic waves have a wide range of wavelengths, from less than 10 picometers (gamma rays) to hundreds of kilometers (radio waves)

- All waves have the same frequency. --> FALSE. As for the wavelength, electromagnetic waves have a wide range of frequencies also.

- All waves travel at $3.00 *10^8 m/s.$ m/s. --> TRUE. This value is called speed of light, and it is one of the fundamental constant: it is the value of the speed of all electromagnetic waves in a vacuum.

- The electric and magnetic fields associated with the waves are perpendicular to each other and to the direction of wave propagation. --> TRUE. Electromagnetic waves are transverse waves, which means that their oscillations (represented by the electric field and the magnetic field) occurs perpendicularly to the direction of motion of the wave.

- The speed of the waves depends on their frequency. --> FALSE. In a vacuum, the speed of ALL electromagnetic waves is always equal to c, regardless of the frequency.