1) Current in each bulb: 0.1 A
The two light bulbs are connected in series, this means that their equivalent resistance is just the sum of the two resistances:
And so, the current through the circuit is (using Ohm's law):
And since the two bulbs are connected in series, the current through each bulb is the same.
2) 4 W and 8 W
The power dissipated by each bulb is given by the formula:
where I is the current and R is the resistance.
For the first bulb:
For the second bulb:
3) 12 W
The total power dissipated in both bulbs is simply the sum of the power dissipated by each bulb, so: