Which has more resistivity

a circuit with one bulb

or a circuit with a bulb strung in series with a pair of bulbs in parallel with one another

- 0 -

or - 0 - =8= -

the one with a bulb strung in series with a pair of bulbs in parallel with one another has more.

Think about it

if pure resistance adds up in series then you have the resistance of one bulb + a non-zero resistance of the two bulbs in parallel > resistance of one bulb

Are you talking about resistivity or resistance? because resistivity is a property of metals that describes how much resistance you have depending on how much of that metal is used in the circuit elements.

R = rho * L / A, for R = resistance, rho = resistivity, L = length of the wire, A = cross sectional area of the wire.

So provided all of the wires are made of the same material, they will all have the same resistivity. However, the circuit with more bulbs will have a greater resistance because the wires are longer (3x coils inside the 3 bulb are longer than 1x coil in 1 bulb, and that's not including the added resistance from the extra wires required to connect the circuit elements together).

edit:

this is a better explanation of why the R is higher in the 2nd circuit. I kind of phoned it in in my reply

err, meant to edit, not quote. My bad

This post was edited by bentherdonethat on Apr 24 2011 11:08pm

ty, i mean reistance sorry.

Furthermore, do we know that the resistances of two objects are equal if their voltages are equal when linked parallel to a battery? Can we not because V= IR and if V is the same, R might differ because I might differ between them depending on their resistance?

If a battery is hooked up to two Resistors that are in parallel, the two resistors don't have to be equal, no. If the resistance in one resistor is greater than in the other, then less current will flow through that resistor. What you have in this case is called a Current Divider.