Troubleshooting Voltmeter Reading w/ Resistance 5*10^4

AI Thread Summary
The discussion revolves around troubleshooting a voltmeter reading with a resistance of 5*10^4 Ohms connected between point b and ground. The user initially attempted to calculate voltage using the formula V = I_fs (R_c + R_s) but encountered discrepancies due to an additive constant. It was clarified that the voltmeter's resistance is in parallel with a 200k-ohm resistor, necessitating the calculation of equivalent resistance to determine the new voltage ratio. The user expressed confusion about the implications of this parallel resistance on their calculations. Ultimately, the user resolved their confusion with assistance from others in the thread.
joshanders_84
Messages
23
Reaction score
0
This is another problem I am having troubles with. Here's the prompt:

What is the reading of a voltmeter with the proper range and with resistance 5*10^4 Ohms when connected between point b and ground?

I know that for voltmeters, V = I_fs (R_c + R_s), and I tried solving for V using the I through the system as I_fs, which I solved as (400V/300000) = .001333, and then using 5*10^4 and 200000 as the resistors, but it says my answer is off by an additive constant. I don't understand what I am dong wrong...all help is appreciated. Thanks
Josh
 

Attachments

  • grounded.jpg
    grounded.jpg
    4 KB · Views: 459
Physics news on Phys.org
If the voltmeter wasn't there, or was perfect, then the voltage at b would be 2/3 of that at a.

Now when the voltmeter is present, its resistance is in parallel with the 200k-ohm resistor, so you can calculate the equivalent resistance of the parallel combination, and get a new ratio for the voltages at a and b.
 
  • Like
Likes berkeman
I don't understand how that helps...sorry. I just don't get what I am doing wrong still, or how the above would help me go further...
 
o i ci I got it now, thank you
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
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

Reading of a voltmeter and an ammeter
Replies
4
Views
3K
Why Don't Voltmeter Readings Across Different Resistors Add to Source Voltage?
Replies
26
Views
5K
Reading of the voltmeter with closed switch
Replies
25
Views
11K
Resistance of the resistor and voltmeter's readings
Replies
25
Views
3K
Voltmeter reading in a parallel circuit with two batteries
Replies
7
Views
3K
How Do You Calculate the Resistance of a Voltmeter?
Replies
6
Views
2K
High voltage circuit with voltmeter in between
Replies
3
Views
2K
The reading of the ammeter and the reading of the voltmeter.
Replies
10
Views
3K
Reading Voltmeters: Constant Terminal Voltages & Resistances
Replies
13
Views
3K
How to Find the Reading of Voltmeters in a Circuit with Identical Resistors?
Replies
5
Views
4K

Hot Threads

Recent Insights

Back
Top