The IEEE 802.11-2012 standard requires VHT capable devices to be backward compatible with devices using which other 802.11 physical layer specification (PHY)?

What is an advantage of using WPA2-Personal instead of WEP-128 as a security solution for
802.11 networks?

What statement about the beamwidth of an RF antenna is true?

You are troubleshooting a client issue on a Windows laptop. The laptop can see and connect to 2.4 GHz APs, but is does not even see 5 GHz APs. While evaluating the issue, you determine that this problem is happening for all of the laptops of this model in the organization. Several other tablets connect on channel 48 and channel 52 in the same work areas. What is the likely problem?

As an RF wave propagates through space, the wave front experiences natural expansion that reduces its signal strength in an area. What term describes the rate at which this expansion happens?