What are brighter 6000K lights or 10000K?

Answer 1

Neither, the brightness varies with the wattage rating not the color temperature rating.

It is called color temperature because the perceived color varies with the color temperature rating. The higher the color temperature the "whiter" the light from the light bulb. Very low color temperatures will result in red or red-orange light, medium color temperatures will result in yellow light, high color temperatures will result in pure white light, and excessively high color temperatures will result in white light with a slightly blue cast (I think 10000K will be blue-white light).

Sometimes it appears to the human eye that a pure white light is brighter than a red or yellow light of the same wattage, but this is not true when measured by a light meter.