Are lost volts the difference between EMF and terminal potential difference?

AI Thread Summary
Lost volts refer to the voltage drop that occurs in a circuit, specifically the difference between electromotive force (EMF) and terminal potential difference (pd). In a typical scenario, such as a voltage divider, the EMF is the open-circuit voltage of a battery, while the terminal pd is the voltage measured across the load. For example, if a cell has an EMF of 1.60V and the terminal pd drops to 1.45V under load, the lost volts would be 0.15V. This concept is often used in educational contexts to illustrate the relationship between current, internal resistance, and voltage drop. Understanding lost volts is crucial for analyzing circuit performance and efficiency.
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Are lost volts the difference between EMF and terminal pd?
 
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By "lost volts" I'm assuming you mean "voltage drop". Can you post a typical circuit that has generated this question?
 
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berkeman said:
By "lost volts" I'm assuming you mean "voltage drop". Can you post a typical circuit that has generated this question?
Actually its a general question, but the circuit used is say for example a potential divider
 
Okay, then what are "EMF" and "terminal pd" in the context of your question? The input battery voltage and the output of the 2-resistor voltage divider?
 
homeworkhelpls said:
Are lost volts the difference between EMF and terminal pd?
Maybe terminology varies regionally, but here in the UK that’s exactly what is meant by ‘lost volts’ for an electrical source.

E.g. a cell’s emf (measured open-circuit) is 1.60V. With some load, the p.d. between the cell’s terminals drops to 1.45V. Then the ‘lost volts’ = 1.60V - 1.45V = 0.15V.

The ‘lost volts’ value is often (especially for teaching and examination purposes here) taken to equal the product of the current through the supply and the supply’s notional internal resistance.
 
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