Currently when you turn on ray tracing, light blocks are completely non-functional as they do not emit any light.
It is also impossible to make them emit light through current resources and PBR capabilities left for creators.

Steps to Produce:
1. Open a ray-tracing capable world or create and enter a world with a ray tracing resource pack and turn ray tracing on.
Note: You can use any RT capable texture pack, however I've provided an "Empty-RT-Capable-RP.mcpack" which is an RT capable RP that uses only vanilla game's files without any alternations, which is suitable for testing for bugs.

2. Give yourself a light block using commands (/give @p light_block)

3. Place down the light block and compare with ray tracing off vs on.

Observed Results:
There is no point light for light blocks with ray tracing. (see images)

Expected Results: 
Light blocks should have a point light with ray tracing and they should emit light just like they do in vanilla game. 

Additional Notes:
Some blocks such as torches and end rods have hard-coded point lights by default because it is impossible to make them emit enough light with the current PBR tools provided to creators.
Light blocks should also emit light for the very same reason, it is not possible to make them emit light with ray tracing through current PBR tools.

Not long ago Deferred Lighting graphics mode got customizable point lights exposed to resource packs (through the global.json file) and this would be a great alternative solution for this issue with ray tracing.

At the very least, please add a constant/fixed point light for the Light block (ideally it should be dynamically changing its intensity to roughly match vanilla light level), it would be much... much better than its current state where it is completely non-functional with ray tracing.