What happens if you pass white light through a blue then a yellow filter? Explain your answer

If you have a blue light, the only light passing through the filter is blue. Yellow things are yellow in white light because they absorb blue light, leaving only the red and green light that our eyes perceive as yellow. So if you put a yellow filter over a blue light, all that's going to happen is that you're going to dim the light a little bit. The light won't suddenly stop being blue, and it won't suddenly change color and become partially red or partially green. Some of it will just get absorbed by the yellow filter. Putting a second yellow filter will absorb even more of the blue light.