Which resistor has most current?

  • Thread starter Thread starter Linus Pauling
  • Start date Start date
  • Tags Tags
    Current Resistor
AI Thread Summary
In the given circuit with an 8V battery, the current can flow through either a 12 ohm resistor (R1) or a combination of a 4 ohm resistor (R2) followed by two 4 ohm resistors (R3 and R4) in parallel. The equivalent resistance of R3 and R4 is 2 ohms, making the total resistance of the path through R2, R3, and R4 equal to 6 ohms, which is less than the 12 ohms of R1. Consequently, the path through R2, R3, and R4 has the most current due to its lower resistance. While R2, R3, and R4 share the same current through R2, the currents through R3 and R4 will differ, as they are in parallel. The ingoing current through R2 equals the sum of the outgoing currents through R3 and R4.
Linus Pauling
Messages
187
Reaction score
0
Circuit: Here's the circuit: there is a 8V battery. The charge leaving it reaches a junction: if the current "turns right" it goes to a 12 ohm resistor (R1) and can then loop around back to the battery, if it goes straight (i.e. takes other path at junction) it runs into a 4 ohm resistor (R2). After the 4 ohm resistor, there are two more 4 ohm resistors (R3 and R4) in parallel (i.e. the equivalent resistor of these two is in series with the first 4 ohm resistor).

Question: Which resistor has the most current going through it?

Relevant equations: resistors in series and in parallel, Kirchoff's loop law

Attempt at solution: If I solve the equivalent resistor for the two 4 ohm resistors in parallel, it's 2 ohms, which is in series with the other 4 ohm resistor, giving 6 ohms. This is less than 12 ohms, so the path "straight ahead" described above (i.e. NOT the path leading to the 12 ohm resistor) is the path of least resistence. Since the first 4 ohm resistor is in series with the equivalent resistor of the other two that are in parallel, then they must have the same current flowing through them by the loop law...

So I was thinking that R2, R3 and R4 would all have the same current through them, but my multiple choice options only include R2, R3, and R4 individually or R3 and R4 together.
 
Last edited:
Physics news on Phys.org
R2 is in series with the equivalent resistor r3//r4, so the same current goes through them, but this does not mean thant the same current goes through r3 or r4.
Consider the point that connects r2, r3 and r4. The ingoing current through r2 must
be equal to the sum of the outgoing currents through r3 and r4.
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
TL;DR Summary: Find Electric field due to charges between 2 parallel infinite planes using Gauss law at any point Here's the diagram. We have a uniform p (rho) density of charges between 2 infinite planes in the cartesian coordinates system. I used a cube of thickness a that spans from z=-a/2 to z=a/2 as a Gaussian surface, each side of the cube has area A. I know that the field depends only on z since there is translational invariance in x and y directions because the planes are...
Back
Top