Potential Difference: Effects of Voltmeter Connection

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Homework Help Overview

The discussion revolves around the effects of connecting a voltmeter across the terminals of a source of electromotive force (emf), specifically focusing on how this connection influences the potential difference measured. The subject area includes concepts of electrical circuits and the behavior of voltmeters in practical scenarios.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the implications of connecting a voltmeter, questioning whether current flows in this scenario and how the voltmeter's resistance affects the current and potential difference. There is also discussion about the internal resistance of batteries and its role in the potential difference observed.

Discussion Status

The discussion is active, with participants raising questions about the nature of voltmeters and their impact on circuit behavior. Some guidance has been offered regarding the ideal versus real characteristics of voltmeters, and the implications of internal resistance in batteries are being examined.

Contextual Notes

There is an assumption that the source of emf under discussion is a battery, and the effects of real-world voltmeter characteristics versus ideal conditions are being considered. The conversation reflects on the nuances of measuring potential difference in practical applications.

tin llenaresas
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what happens to the potential difference of a source of emf when a voltmeter is connected across its terminals?
tanx. :smile:
 
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HINT: Does current flow when the voltmeter is connected?
 
hey tide,

ideal voltmeters should have infinite resistance so as not to alter current but real voltmeters have finite resistance.does our voltmeter, in any way, still alter the current flowing through our set-up?
 
I assume that the source of EMF that you have in mind is a battery. Batteries have internal resistance and if there is current flowing through the battery then, by Ohm's Law, there must be a potential difference across the resistance.
 
so, does the voltmeter affects the potential difference of a source?
 
Yes, the potential difference across the battery will decrease but still the emf of the source remains the same. The emf of a source is the energy supplied by the source per unit charge and is measured by the potential difference across the terminals, when no current is flowing through the source.
 

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