Calculate the emf of Battery w/ External & Internal Resistance

AI Thread Summary
The discussion revolves around calculating the electromotive force (emf) of a battery with given external and internal resistances. The external resistance is 2.50 ohms, and the current is 4.0 A, while the internal resistance is 0.50 ohms. The user applies the equations V = IR and E = V + Ir to find the voltage across the external resistance as 10V and the emf as 12V. Responses confirm that the user's logic and calculations appear correct, assuming no unusual diagram details. The final emf of the battery is therefore 12V.
Jabababa
Messages
52
Reaction score
0

Homework Statement


What is the emf of the battery shown?

there is an external resistance of 2.50 ohm and 4.0 A...The battery has an internal resistance of 0.50ohm

Homework Equations



V=Ir
V= E +/- IR


The Attempt at a Solution



Since the current is going away the battery then i use the equation V= E - Ir
To find the V of the whole battery V= IR, V=(4)(2.5) = 10V
E= V + Ir
E= 10 + (4)(0.5) = 12 V

please check see if its right. If I am not clear i can upload a picture.
 
Physics news on Phys.org
Jabababa said:

Homework Statement


What is the emf of the battery shown?

there is an external resistance of 2.50 ohm and 4.0 A...The battery has an internal resistance of 0.50ohm

Homework Equations



V=Ir
V= E +/- IR


The Attempt at a Solution



Since the current is going away the battery then i use the equation V= E - Ir
To find the V of the whole battery V= IR, V=(4)(2.5) = 10V
E= V + Ir
E= 10 + (4)(0.5) = 12 V

please check see if its right. If I am not clear i can upload a picture.

Again your logic appears good - unless the diagram is quite unusual.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

How to solve for EMF and internal resistance in a circuit?
Replies
8
Views
3K
Internal Resistance of a Car Battery
Replies
8
Views
13K
Find Internal Resistance From 2 Circuits w/ The Same Battery
Replies
2
Views
2K
Potential difference of an emf with internal resistance
Replies
4
Views
2K
Unraveling the Mystery of EMF Internal Resistance
Replies
2
Views
2K
Calculating EMF and Load Resistance for a Motor
Replies
11
Views
2K
Batteries in series, parallel, and internal resistance
Replies
24
Views
5K
I''What is the optimal resistance for maximizing battery terminal voltage?
Replies
2
Views
1K
Why formula for internal resistance for charging battery v = e + Ir
Replies
3
Views
2K
Finding the internal resistance of battery
Replies
10
Views
3K

Hot Threads

Recent Insights

Back
Top