Calculate Current Through Battery Connected to Resistor

  • Thread starter Thread starter katiemc124
  • Start date Start date
  • Tags Tags
    Circuits Emf
Click For Summary
SUMMARY

The discussion centers on calculating the current (I) through a battery connected to a 21-ohm resistor, given an electromotive force (emf) of 12V. The formula used is I=emf/(R+r), where R represents the external resistance and r denotes the internal resistance of the battery. The user faced challenges due to the lack of information regarding the internal resistance, which is crucial for accurate calculations. The conversation highlights the importance of understanding both external and internal resistances in circuit analysis.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with electromotive force (emf)
  • Knowledge of internal resistance in batteries
  • Basic circuit analysis techniques
NEXT STEPS
  • Research internal resistance of batteries and its impact on circuit performance
  • Learn how to measure internal resistance using multimeters
  • Explore advanced circuit analysis techniques, including Thevenin's theorem
  • Study practical applications of Ohm's Law in real-world circuits
USEFUL FOR

Students studying electrical engineering, hobbyists working with circuits, and anyone interested in understanding battery performance and circuit calculations.

katiemc124
Messages
2
Reaction score
0

Homework Statement



The voltmeter is removed (previous question was a voltmeter connected to a battery and it reads 12 V) and a resistor of 21 ohm is connected to the battery. What is the current (I) through the battery?


Homework Equations



emf=V
I=emf/(R+r)

The Attempt at a Solution



I tried to do I=12V/21 ohm but I don't know how to find R. When I entered the solution of that, it said to include the internal resistance of the battery, but I don't know the current of the battery so I can't use emf=IR to find R.
 
Physics news on Phys.org
Is there an answer in the back of the book to compare to?
 
haha nevermind. I was having trouble because I didn't have enough information, but I just didn't see where it was written. Thanks for your help anyway!
 

Similar threads

Why do the headlights on the car become dim when the car is starting?
  • · Replies 4 ·
Replies
4
Views
2K
Circuit with potential difference across battery being zero?
  • · Replies 3 ·
Replies
3
Views
2K
Introduce a battery to an LR circuit
  • · Replies 16 ·
Replies
16
Views
1K
Voltmeter readings for this circuit with switches
  • · Replies 17 ·
Replies
17
Views
2K
How to Determine the EMF of a Battery Using Two Voltmeters?
  • · Replies 7 ·
Replies
7
Views
2K
Current through a circuit when the key is open
  • · Replies 42 ·
2
Replies
42
Views
6K
Find the inductance of an inductor in a circuit
  • · Replies 18 ·
Replies
18
Views
3K
Mechanisms Involved When Charging a Battery
  • · Replies 10 ·
Replies
10
Views
2K
Ohm's Law - Finding Source Voltage
  • · Replies 3 ·
Replies
3
Views
2K
Unraveling the Mystery of EMF Internal Resistance
  • · Replies 2 ·
Replies
2
Views
2K