# Equivalent Resistance

The question was to rank from highest to lowest equivalent resistance. This is what I came up with, but it was counted wrong and I don't understand why.

http://i324.photobucket.com/albums/k327/ProtoGirlEXE/100_0687-1.jpg [Broken]

The equivalent resistance of resistors in series are added while in parallel the reciprocal is added.

Each resistor as the same R, so I used R=2

Here are my numbers, in the order that I ranked, wronging:

1. (1/2) + .5= 1 + 2= 3

2. 2

3. .5+ .5+ .5= 1.5

4. .5 + .5= 1

5. 2+2 = 4
(1/4)+ .5 = .75

Last edited by a moderator:

Related Introductory Physics Homework Help News on Phys.org
kuruman
Homework Helper
Gold Member
It would be easier to troubleshoot your answers if you presented them in the order of the figures left to right. However, just by looking at what you have, I see no figure that shows two resistors in series corresponding to 2+2=4.

3. .5+ .5+ .5= 1.5

5. 2+2 = 4
(1/4)+ .5 = .75
How have you done these??? they seems to be wrong

I see no figure that shows two resistors in series corresponding to 2+2=4.
Its for upper part of last figure which he has done correctly

_________________

I guess you have solving parallel connections

How have you done these??? they seems to be wrong[/QUOTE

Since R is equal in every resistor, I chose R=2

so for parallel the R is summed by the reciprocal (1/2)=.5
in series they are summed

for parallel,

$$\frac{1}{R_{net}} = \frac{1}{R_1} + \frac{1}{R_2} \ ...$$

$$\frac{1}{R_{net}} = \frac{1}{R_1} + \frac{1}{R_2} \ ...$$