If 300,000 cycles occur in one second, what is the frequency?

• A. 3 MHz
• B. 30 kHz
• C. 300 MHz
• D. 300 kHz

Answer: (D)

Frequency is the number of cycles that occur every second. If 300,000 cycles happen in one second, the frequency is 300,000 Hz. Converting to kilohertz gives 300 kHz, since 1 kHz = 1,000 Hz. You can also see it as 0.3 MHz, which is the same value as 300 kHz. The other readings would correspond to 3,000,000 Hz (3 MHz), 30,000 Hz (30 kHz), or 300,000,000 Hz (300 MHz), which do not match 300,000 cycles per second. So the frequency is 300 kHz.