In a WLAN network, which of the following protocols cannot work in the 2.4 GHz frequency band?

Question

Options

• A802.11ac
• B802.11g
• C802.11ax
• D802.11n

• A
  2% (1)
• B
  80% (39)
• C
  6% (3)
• D
  12% (6)

Explanation

There appears to be an error in the provided answer key. The correct answer is actually A (802.11ac), not B.

802.11ac is the only protocol listed that cannot operate in the 2.4 GHz band - it is a 5 GHz-only standard (Wi-Fi 5), designed exclusively for that frequency to achieve higher throughput. 802.11g (choice B) is actually a 2.4 GHz-only standard, so it absolutely works in that band - making it a wrong answer to this question. 802.11n (Wi-Fi 4) and 802.11ax (Wi-Fi 6) are both dual-band protocols that operate on both 2.4 GHz and 5 GHz, so they also work in 2.4 GHz.

Memory tip: Think of the "ac" in 802.11ac as standing for "Always 5 GHz, Can't do 2.4." It's the last single-band standard before Wi-Fi 6 introduced tri-band support.

Summary of bands:

Protocol	2.4 GHz	5 GHz
802.11g	Yes	No
802.11n	Yes	Yes
802.11ac	No	Yes
802.11ax	Yes	Yes

You may want to verify the answer key with your source - it appears to contain a typo (B instead of A).

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