New Reply

Find the current and potential difference

 
Share Thread Thread Tools
Mar11-11, 08:23 PM   #1
 

Find the current and potential difference


1. The problem statement, all variables and given/known data
For the circuit shown in the figure, find the current through and the potential difference across each resistor.
http://session.masteringphysics.com/...ure.23.P60.jpg


2. Relevant equations
V=I(amps)/R(ohms) and Req=R1+R2+R3.....


3. The attempt at a solution
Rearranging the circuit:
R(8ohm) and R(24ohm) are parallel so (1/8+1/24)^-1=6ohm
that created a series of R(6ohm)+R(6ohm) so R6+R6=R(12ohm)
now I have the first circuit R(4ohm) in parallel with R(12ohm) and R(24ohm)
(1/4+1/12+1/24)^-1=2.67ohm for equivalent resistance for the entire circuit

24V=I*2.67ohm
I=9Amps

across the 4ohm resistor the current is? I=9A because the current is the same or is it 9A divided across the 3 parallel resistors?

I'm either getting it wrong because I put the 4ohm by itself (before the junction correct?) or if it's in series with the 2 6ohm resistors then that's my error but I've definitely tried it 4 different ways and am getting something wrong.
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
PhysOrg.com
PhysOrg
science news on PhysOrg.com

>> Ants and carnivorous plants conspire for mutualistic feeding
>> Forecast for Titan: Wild weather could be ahead
>> Researchers stitch defects into the world's thinnest semiconductor
Mar11-11, 09:02 PM   #2
 
Mentor
Quote by spice1510 View Post
1. The problem statement, all variables and given/known data
For the circuit shown in the figure, find the current through and the potential difference across each resistor.
http://session.masteringphysics.com/...ure.23.P60.jpg


2. Relevant equations
V=I(amps)/R(ohms) and Req=R1+R2+R3.....


3. The attempt at a solution
Rearranging the circuit:
R(8ohm) and R(24ohm) are parallel so (1/8+1/24)^-1=6ohm
that created a series of R(6ohm)+R(6ohm) so R6+R6=R(12ohm)
now I have the first circuit R(4ohm) in parallel with R(12ohm) and R(24ohm)

No, the 12Ω and 24Ω are in parallel. The 4V is in series with the (12V & 24V) combination.

(1/4+1/12+1/24)^-1=2.67ohm for equivalent resistance for the entire circuit

24V=I*2.67ohm
I=9Amps

across the 4ohm resistor the current is? I=9A because the current is the same or is it 9A divided across the 3 parallel resistors?

I'm either getting it wrong because I put the 4ohm by itself (before the junction correct?) or if it's in series with the 2 6ohm resistors then that's my error but I've definitely tried it 4 different ways and am getting something wrong.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
See the comment in red.
Mar11-11, 09:16 PM   #3
 
so 4ohm in series with (1/12+1/24)^-1 which equals 8ohm

4ohm+8ohm (series)=12ohm for the entire circuit

24V=12ohm*I
I=2amps
Mar12-11, 11:18 PM   #4
 
Mentor

Find the current and potential difference


Quote by spice1510 View Post
so 4ohm in series with (1/12+1/24)^-1 which equals 8ohm

4ohm+8ohm (series)=12ohm for the entire circuit

24V=12ohm*I
I=2amps
Yes.

Now, work your way back through all the resistors.
New Reply
Thread Tools


Similar Threads for: Find the current and potential difference
Thread Forum Replies
Current Direction vs. Potential Difference General Physics 2
Current due to Potential Difference Introductory Physics Homework 2
What's the Current of the Potential Difference? Introductory Physics Homework 2
Potential difference and current Introductory Physics Homework 1
EMF, Voltage, Current, Potential Difference etc. Introductory Physics Homework 6