Calculating combined resistance of wires

• toforfiltum
In summary, the conversation discusses calculating the net resistance of resistors in parallel, specifically in regards to six copper wires and a steel core. The correct answer is B, 1.6Ω, which only takes into account the resistance of the six copper wires. The conversation also briefly touches on the idea of using one copper wire of the same cross-sectional area as a power cable.
toforfiltum

• R ∝ 1/A

The Attempt at a Solution

Since there are six copper wires and a steel core, I added the resistance of all the wires and the core and divided them by 7, though I don't think my approach is right since the resistance of the copper and steel wires are different. As such my answer is about 22.9Ω, which is wrong. The answer is B, 1.6Ω, which is just the quotient of the the total resistance of the six copper wires. Why is the resistance of steel core not taken into account in this case?

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Do you know how to calculate the net resistance of resistors in parallel?

Ermm...yes. But why is the steel not taken into account?

toforfiltum said:
Ermm...yes. But why is the steel not taken into account?
Why are you so sure it isn't? Have you done the calculation taking the steel into account?

Oh, so is the working 6(1/10) + 1/100 correct for 1/R?

toforfiltum said:
Oh, so is the working 6(1/10) + 1/100 correct for 1/R?
Yes.

Thanks. So is this combined resistance of six different copper wires and steel less than a power cable just made up of one copper wire of the same cross-sectional area?

toforfiltum said:
Thanks. So is this combined resistance of six different copper wires and steel less than a power cable just made up of one copper wire of the same cross-sectional area?
What do you think?

I think the resistance of six different copper wires and the steel would be lesser. However if it's just the six copper wires without the steel, then they would be the same.

toforfiltum said:
I think the resistance of six different copper wires and the steel would be lesser. However if it's just the six copper wires without the steel, then they would be the same.
Quite so.

Why quite so? Is it not really correct?

toforfiltum said:
Why quite so? Is it not really correct?
"Quite so" means, yes, that is exactly correct. (British English idiom?)

toforfiltum
Oh I see.

Since resistance values are given we need think about type of wire.
From situation they are in parallel connection.

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Neelima said:
Since resistance values are given we need think about type of wire.
From situation they are in parallel connection.
Yes, the OP got this in post #5. Five years ago.

etotheipi

What is the formula for calculating combined resistance?

The formula for calculating combined resistance is R = R1 + R2 + R3 + ... + Rn, where R is the total resistance and R1, R2, R3, etc. are the individual resistances of each wire in the circuit.

How do you calculate the combined resistance of wires in series?

To calculate the combined resistance of wires in series, simply add the individual resistances of each wire together.

How do you calculate the combined resistance of wires in parallel?

To calculate the combined resistance of wires in parallel, use the formula 1/R = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn, where R is the total resistance and R1, R2, R3, etc. are the individual resistances of each wire.

What is the difference between series and parallel circuits?

In a series circuit, the components are connected one after the other, creating only one path for the current to flow. In a parallel circuit, the components are connected in separate branches, creating multiple paths for the current to flow.

Can the combined resistance of wires ever be less than the individual resistances?

No, the combined resistance of wires can never be less than the individual resistances. In series circuits, the total resistance is always greater than each individual resistance, and in parallel circuits, the total resistance is always less than each individual resistance.

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