what are advanteges and disadvantages of a series circuit. and how does a variable resistor wo???

Answer 1

Series circuits have two disadvantages when compared with parallel circuits.

The first disadvantage is that, if one component in a series circuit fails, then all the components in the circuit fail because the circuit has been broken.

The second disadvantage is that the more components there are in a series circuit, the greater the circuit's resistance*.

AND ...

A variable resistor is a potentiometer with only two connecting wires instead of three. However, although the actual component is the same, it does a very different job. The pot allows us to control the potential passed through a circuit. The variable resistance lets us adjust the resistance between two points in a circuit.

Answer 2

disadvantage: when a bulb burn, the rest will not light up...
advantage: it needs lesser wires...(if you are shortage of them...)
variable resistor works by controlling the brightness of a bulb...