Are NXT Light sensors compatible with EV3? I would like to use the NXT light sensors with my EV3 brick. I don't have enough light sensors as I need 2 for each robot (per set) and it only comes with one. However, I have a lot of NXT sensors. Will the EV3 be able to use the NXT light snesor and is the NXT light sensor as accurate as the EV3 light sensor?
NXT Color Sensors are supported directly by EV3-G, the EV3 software running on the PC or MAC.
NXT Light Sensors are not.

To use Light sensors requires a bit of trickery.  EV3-G has a Raw Sensor block that provides access to the Light sensor values.  The raw sensor returns values from 0-1023, which is very different than the 0-100 of the NXT-G Light Sensor block.

Setting up the Light sensor to use ambient or reflected light is also solved with a bit of trickery.  Use the Sound Sensor Block and toggle the dB setting.

Once that much is tested and working, create a set of MyBlocks to mimic existing Color Sensor blocks.