Answer: A device that uses infrared sensors.
Explanation:
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:

Explanation:
When a man falls on a hard cemented floor his momentum reduced to zero in a very short time and hurt the man. Whereas when a man falls on a heap of sand. As sand can compress, it takes longer time for the man to hit the ground (or hard surface)
Answer is A of course lol Fire needs oxygen as an essential fuel to burn.