Answer:
Power of the bulb is 10 Watts.
Step-by-step explanation:
We have,
Power and voltage of electric bulb is 40 W and 200 V. Using this data we can find the resistance of the bulb.
Power,

R is resistance

The supplied voltage is 100 V.
Now power is given by :

So, now the power of the bulb is 10 Watts.