The usable radio frequency range extends from 10 kHz to which upper limit?

• A. 100 Hz
• B. 100 kHz
• C. 100 MHz
• D. 100 GHz

Answer: (D)

The key idea is understanding the span of usable radio frequencies. In many IT2 study materials, the usable RF range starts at about 10 kHz and extends up into the microwave region, with a common upper limit given as 100 GHz. That means the highest frequency included in this typical range is 100 GHz, which is why that choice is the best fit for the upper limit.

The other options don’t fit as the upper boundary. 100 Hz is below the stated lower bound of 10 kHz, so it can’t be the upper limit. 100 kHz lies above the lower end but well below the upper limit. 100 MHz is also within the range but still far below 100 GHz, so it’s not the maximum frequency described.