FC0-U71 Infrastructure Practice Question
Which of the following Wi-Fi standards operates on the 5 GHz band and provides the fastest theoretical speeds?
⚠ Common exam trap
The trap is that 802.11ac is also a 5 GHz standard with impressive speeds, so candidates who don't know the chronological order (n → ac → ax) pick ac as 'fastest' — remember ax is newer and faster than ac.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
802.11ax
IEEE 802.11ax (marketed as Wi-Fi 6 and Wi-Fi 6E) is the newest standard listed and delivers the fastest theoretical throughput, up to roughly 9.6 Gbps, while operating on both 2.4 GHz and 5 GHz bands (and 6 GHz for Wi-Fi 6E). It introduces OFDMA, MU-MIMO, and 1024-QAM to boost efficiency and speed in dense environments. This makes it the correct answer for 'fastest theoretical speeds on the 5 GHz band.'
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
802.11g
Why it's wrong here
802.11g operates only on the 2.4 GHz band, capping theoretical throughput at 54 Mbps, so it fails both the band and speed requirements. It is tempting because 802.11g was a mainstream, widely deployed standard for home routers, and would be the right answer if the question asked about 2.4 GHz backward compatibility.
- ✓
802.11ax
Why this is correct
802.11ax (Wi-Fi 6) operates on both 2.4 GHz and 5 GHz bands and delivers the highest theoretical throughput of the listed standards, using OFDMA and higher-order modulation. This satisfies the question's requirement for the fastest speeds on the 5 GHz band.
- ✗
802.11ac
Why it's wrong here
802.11ac does operate on 5 GHz and reaches multi-gigabit theoretical speeds, but the question asks for the fastest, and 802.11ax (Wi-Fi 6) exceeds it. It is tempting because 802.11ac is the well-known 5 GHz workhorse, and would be correct if 802.11ax were not among the listed options.
- ✗
802.11n
Why it's wrong here
802.11n supports 5 GHz, but its theoretical maximum of 600 Mbps is lower than 802.11ac's multi-gigabit rates, so it fails the fastest-speed requirement. It is tempting because 802.11n was the first standard to introduce 5 GHz alongside MIMO, and would be correct if the question asked which standard introduced dual-band support.
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Same concept, more angles
2 more ways this is tested on FC0-U71
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which wireless standard operates on both 2.4 GHz and 5 GHz bands, providing faster speeds and better performance in crowded environments compared to its predecessor?
easy- A.802.11n
- B.802.11g
- ✓ C.802.11ax
- D.802.11ac
Why C: 802.11ax (Wi-Fi 6) operates on both the 2.4 GHz and 5 GHz bands and introduces OFDMA, MU-MIMO, and BSS Coloring, which significantly improve performance in dense, crowded environments compared to 802.11ac. It is the successor to 802.11ac and is designed specifically to handle high-density deployments like stadiums, offices, and campuses. 802.11ac, by contrast, operates only on 5 GHz, so it cannot be the correct answer.
Variation 2. Which wireless standard is commonly known as Wi-Fi 5 and operates on the 5 GHz band?
medium- A.802.11ax
- B.802.11g
- C.802.11n
- ✓ D.802.11ac
Why D: 802.11ac is the IEEE standard marketed as Wi-Fi 5, and it operates primarily on the 5 GHz band (with some early dual-band implementations). It introduced wider channels (up to 160 MHz), MU-MIMO, and higher-order modulation to boost throughput over 802.11n. This makes 802.11ac the correct answer for Wi-Fi 5 on 5 GHz.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This FC0-U71 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the FC0-U71 exam.