How Do I Solve a Parallel Circuit Problem?

Click For Summary
The discussion focuses on solving a parallel circuit problem involving resistors of 5 ohms and 20 ohms in parallel, combined with a 50-ohm resistor in series. The equivalent resistance for the parallel resistors is calculated using the formula 1/R_eq = 1/R1 + 1/R2, resulting in an equivalent resistance of 4 ohms in parallel with the 50 ohm resistor. The total resistance of the circuit is determined to be 54 ohms, allowing for the calculation of total current using V=IR. The current is then divided between the parallel resistors, with the majority flowing through the lower resistance. The calculations provided confirm the accuracy of the approach taken.
fcb
Messages
50
Reaction score
1

Homework Statement



27zztrc.png

Homework Equations



V=IR and What not

The Attempt at a Solution



I have attempted it many different ways
I need your help, I have preliminary exams coming up, Please do me a favour.

Regards, FCB
 
Physics news on Phys.org
Show at least one attempt.
 
ok so we have 5 ohm and 20 ohm , in parallel, which are both in series with 50ohm

now for equivalent resistance in parallel

1 / R eq= 1/R1 + 1/R2

ie R eq= R1 * R2 / ( R1+R2)

therefore we have ( 4ohm in series with 50 ohm)

then R eq= 54ohm ( add them when in series )

then apply v=IR to get total current in circuit

I= V/R
= 12 / 54

now when this current gets to the section where it splits in two, the current is divided and the majority of current goes throguh the least resistance

current through 5ohm = 20 / ( 25) * 12 / 54
current through 20ohm = 5 / ( 25) * 12/54
 
Your calculations are correct.
 
Thread 'Correct statement about size of wire to produce larger extension'
The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and ##L## and decrease ##A## I am not sure whether there is change in ##F## for first and second wire so I will just assume ##F## does not change. It leaves (B) and (C) as possible options so why is (C)...

Similar threads

  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
2
Views
6K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
14
Views
668
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 13 ·
Replies
13
Views
1K
Replies
3
Views
2K
  • · Replies 9 ·
Replies
9
Views
1K