What is the Resistance of Resistor X?

  • Thread starter Thread starter Soaring Crane
  • Start date Start date
  • Tags Tags
    Resistors
AI Thread Summary
The discussion revolves around calculating the resistance of resistor X in a network where an ohmmeter reads 20.2 ohms. The user attempts to determine if the 75.0 ohm and 55.0 ohm resistors are in series, leading to a combined resistance of 115.0 ohms, which is then used in a parallel calculation with other resistors. The user applies the formula for equivalent resistance in parallel circuits but expresses uncertainty about their approach and whether they considered all necessary properties of ohmmeter readings. After calculations, they arrive at a resistance value of approximately 46.8 ohms for resistor X. Overall, the user seeks confirmation of their method and results.
Soaring Crane
Messages
461
Reaction score
0

Homework Statement



For the resistor network shown in the figure, the ohmmeter reads 20.2 ohm.

yf_Figure_26_491.jpg


What is the resistance of the resistor X?


Homework Equations



See below.

The Attempt at a Solution



I’m uncertain if I tackled the system correctly, so please guide me on any misconceptions in my workings.

For an ohmmeter, I didn’t come across any special formulas like for a voltmeter, and I may have not addressed any typical properties for ohmmeter readings . . .

Are the 75.0 ohm and 55.0 ohm in series? And then X; R_75+55; R_115, and R_85 will be in parallel?

(1/R_eq) = (1/R_x) +(1/115.0 ohm) +(1/130.0 ohm) + (1/85 ohm)
(1/R_x) = (1/20.2 ohm) – (1/115.0 ohm) –(1/130 ohm) – (1/85 ohm)
= 0.02135 1/ohm

R_x = 1/0.0214 1/ohm = 46.8 ohm ?

Thanks.
 
Physics news on Phys.org
Looks good to me!
 
Thread 'Variable mass system : water sprayed into a moving container'

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}...
View full post »

Similar threads

Finding Optimal Fixed Resistor for Potential Divider Circuit
Replies
45
Views
4K
What is the relationship between resistors in a circuit?
Replies
15
Views
2K
Solve emf of battery with resistors and voltmeter
Replies
4
Views
6K
What Is the Correct Way to Calculate Resistance in Complex Resistor Networks?
Replies
4
Views
5K
Working out EMF and internal resistance
Replies
3
Views
2K
What is the Resistance R for 295 Watts Dissipation in a Network of Resistors?
Replies
4
Views
2K
Kirchoff's Laws Problem Current
Replies
11
Views
2K
Resistance and Current-Direct Current Circuits
Replies
7
Views
3K
What is the resistance of the voltmeter in this series circuit?
Replies
2
Views
1K
Circuits: What does the voltmeter read?
Replies
3
Views
12K

Hot Threads

Recent Insights

Back
Top