Question

select the correct answer.
which statement is true about the electromagnetic spectrum?

a. the visible spectrum includes radio waves, light, and gamma rays.

b. the colors you can see have the same wavelength.

c. it has a range of visible and invisible forms of radiation.

d. the waves travel at the speed of $2.998\times10^5$ meters/second.

Explanation:

• Option A: The visible spectrum is only a small part of the electromagnetic spectrum and does not include radio waves or gamma rays. Radio waves and gamma rays are invisible forms of electromagnetic radiation, so A is incorrect.
• Option B: Different colors in the visible spectrum have different wavelengths. For example, red light has a longer wavelength than blue light, so B is incorrect.
• Option C: The electromagnetic spectrum includes visible light (like the colors we can see) and invisible forms of radiation such as radio waves, microwaves, infrared, ultraviolet, X - rays, and gamma rays. So this statement is true.
• Option D: Electromagnetic waves travel at the speed of light, which is approximately \(2.998\times10^{8}\) meters per second, not \(2.998\times10^{5}\) meters per second, so D is incorrect.

Answer:

C. It has a range of visible and invisible forms of radiation.