A pure sine wave contains how many frequency components?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (A)

A pure sine wave is a single-frequency tone. When you look at its frequency content, there is only one component present—at the sine’s fundamental frequency. In an ideal sine, there are no harmonics or additional frequencies, so the spectrum is just a single spike. In the real world, small distortions or noise might add tiny extras, but the essence remains that a pure sine carries one frequency component. By contrast, other waveforms like square, sawtooth, or triangle waves contain multiple frequency components (harmonics), which is why they sound richer or more complex.