The bulb is the load of the circuit, without it you have a short circuit.
Yes, light bulbs can be powered by a parallel circuit.
When two light bulbs are in place, there will be a circuit created where electricity can flow through both bulbs. If the circuit is intact and the bulbs are functioning, they will both light up. If one of the bulbs is faulty or the circuit is broken, then both bulbs may not light up.
Parallel.
Do nothing. But in a parallel circuit, all the bulbs will get dimmer.
Of course. The circuit in my house has two door buzzers and almost 30 bulbs.
As the number of bulbs in a series circuit increases, the current decreases. As the number of bulbs in a parallel circuit increases, the current increases.
nothing
Parallel
Parallel circuit
Loosening one bulb in a series circuit will break the circuit and cause all the bulbs to turn off. In a parallel circuit, loosening one bulb will not affect the other bulbs, and they will remain lit.
Bulbs in a parallel circuit draw the same amount of current, so each will display the same brightness. Bulbs in a series circuit share the current so all bulbs will appear dimmer.
In a series circuit, all bulbs are necessary to complete the circuit. If one bulb goes out, the circuit is broken, so none of the bulbs would light up.