Is the brightness of a 220 v.100 w incandescent lamp connected to a 220 V DC power supply the same as that of a 220 V AC power supply? Why?

Is the brightness of a 220 v.100 w incandescent lamp connected to a 220 V DC power supply the same as that of a 220 V AC power supply? Why?

The brightness is the same, because that's the definition of the AC RMS

Is there any difference between the light bulb with rated voltage of 220 V connected to 220 V AC power supply and 220 V DC power supply? Which light bulb is on

No difference, the same light
The voltage range of 220 V AC is - 380 V to + 380 V, which fluctuates up and down in sin (x) curve, but the output power is equal to that of 220 V DC, so it is called 220 V AC. when the light bulb is connected, the output power of current is the same, so it is also on