in the circuit diagram even in suppose the resistor R1 R2 and R3 have the value of 5 ohm 10 ohm 30 ohm respectively which have been connected to a battery of 12 volt calculate the current through the each resistor be the total current in the circuit and see the total circuit resistance

Three identical resistors of resistances 5Ω, 10Ω and 30Ω are connected with a battery of 12V

We have to find current through the each resistor and equivalent resistance of circuit

➝ Equivalent resistance of series connection is given by

➝ We know that, Equal current flow through each resistor in series connection.

➝ As per ohm's law, Current flow through a conductor is directly proportional to the applied potential difference.

◈ Equivalent resistance :

⇒ Req = R1 + R2 + R3

⇒ Req = 5 + 10 + 30

⇒ Req = 45Ω

◈ Current flow in circuit :

⇒ V = IReq

⇒ 12 = I × 45

⇒ I = 0.27A

፨ Therefore, 0.27A current will flow through each resistor.

magnitude and direction

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).