That would be a parallel circuit.
That would be a parallel circuit.
That would be a parallel circuit.
Since the SAME electrons have to go through both light bulbs, the current in both light bulbs will be the same (Kirchhoff's current law).
The two bulbs will be wired in parallel with each other. The switch will be wired into the circuit upstream of the bulbs.
The question is ambiguous, however one possibility is a parallel circuit, which would permit one light bulb to remain lit while the other light bulb was switched off. By contrast, if the light bulbs were connected in a series circuit, switching one light bulb off would cause both lights to go off.
the circuit must be wired in parallel.
reduces it from 1/2 to 1/3rd
If a circuit is wired in parallel, all the bulbs have their own independent access to electricity, so if one bulb goes out, the others are not affected. If the circuit is wired in series, then one bulb going out will block the current to all the other bulbs as well.
The brightness of the lights may or may not change depending on the circuit in which they are wired. In a series circuit, all the bulbs (called lamps) will experience the same current flow. The same amount of current will be flowing through each one, and each one will be dropping some amount of voltage. If we remove some of the lamps and reconnect the circuit, the lamps will glow brighter because there is less total resistance in the circuit. The remaining lamps will end up dropping more voltage, and will glow brighter. In a parallel circuit, removing bulbs (or adding them) will not affect the operation of the other lamps in the circuit (providing the voltage source is adequate). We know that each of the lights in a household circuit is wired in parallel, and turning one or more on or off won't affect the operation (the brightness) of any other light that is on.
Can't answer that w/o knowing the Ampere rating of the fuse. A standard house circuit being 15 amps you would load the circuit up to 14.7 amps with 27 light bulbs.
I you wired a light bulb in to the same circuit you have the possibility of over loading the circuit but other than that it would just be brighter.
As a series circuit, as asked, all bulbs will go off because of that just one bulb.