Electric Potential: Resistor, Battery, Voltmeter - What is the PD?

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SUMMARY

The discussion clarifies the concept of potential difference (p.d.) in an incomplete circuit involving a resistor and a battery with an electromotive force (emf) of 5V. When a voltmeter is connected across the resistor, the p.d. is zero because no current flows due to the incomplete circuit, as dictated by Kirchhoff's Current Law. However, the potential from the open end of the resistor to the wire connected to the negative terminal of the battery remains at 5V. This distinction emphasizes the importance of understanding relative potentials in electrical circuits.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Familiarity with Kirchhoff's Current Law
  • Basic knowledge of electric potential and voltage
  • Concept of electromotive force (emf)
NEXT STEPS
  • Study the implications of Kirchhoff's Current Law in circuit analysis
  • Explore the relationship between voltage, current, and resistance using Ohm's Law
  • Learn about electric potential in complete versus incomplete circuits
  • Investigate the behavior of voltmeters in various circuit configurations
USEFUL FOR

Students of electrical engineering, educators teaching circuit theory, and hobbyists working with basic electronic circuits will benefit from this discussion.

Kushal
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hi...

if you got resistor, having its positive terminal attached to the positive end of a battery (say emf 5V), and the negative end left connected to a simple wire, as such...in short, the circuit is not complete.

what is the pd when a voltmeter is connected across the resistor?

is it zero, or 5V??

and what is the potential, at any point on the wire connected to the negative terminal of the resistor?

thnks
 
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The p.d. is zero. Potentials only make sense relatively. In this case, the potential is the same as the +ve end of the battery.
 
oooiee...thnks
 
Ohm's Law: V=IR
V = voltage across resistor
I = current through resistor
Current cannot flow since the circuit is incomplete (Kirchoff's Current Law).
I = 0,
regardless of R, V = 0
The p.d. across the resistor is zero, but the p.d. from the open end of the resistor to the "simple wire" is 5V.
 

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