As more and more bulbs are connected in series to a flashlight battery, what happens to the brightness of each bulb? assuming that heating inside the battery is negligible, what happens to the brightness of each bulb when more and more bulbs are connected in parallel?

so each bulb brightness becomes half of its given or indicated power

so both bulb will glow same power as indicated

Explanation:

Let the indicated power on the bulbs is given as P and its rated voltage is V

so here resistance of each bulb is given as

now if the two bulbs are connected in series so we will have

now the current in the circuit is given as

now brightness of each bulb is given as

so each bulb brightness becomes half of its given or indicated power

Now if the two bulbs are connected in parallel

then the net voltage across each bulb is "V"

so we will have

so both bulb will glow same power as indicated