why during discharging: Terminal p.d. V < emf E. V = E-Ir During recharging: Terminal p.d. V > emf E. V = E+Ir?? why???why??
Asked by imattop | 24th Feb, 2011, 12:00: AM
Expert Answer:
Dear student,
Electromotive force is the voltage of your battery.
It is the MAXIMUM voltage the circuit can attain. So, when you place a voltmeter in parallel to your battery/cell, the reading shown is your Electromotive Force, or EMF.
Whereas, PD or potential difference is simply the difference of the voltage before and after experiencing a resistance effect. So basically, the potential difference can never be equal to the EMF in a circuit because there is always energy lost as heat, or some other form.
1) during discharge: terminal V < emf, due to the voltage drop from internal resistance
2) during recharge: terminal V > emf, due to restoration of potential difference across the terminals of the battery (i.e. voltage source)
Hope this helps.
Team
Topperlearnin g.com
It is the MAXIMUM voltage the circuit can attain. So, when you place a voltmeter in parallel to your battery/cell, the reading shown is your Electromotive Force, or EMF.
Whereas, PD or potential difference is simply the difference of the voltage before and after experiencing a resistance effect. So basically, the potential difference can never be equal to the EMF in a circuit because there is always energy lost as heat, or some other form.
2) during recharge: terminal V > emf, due to restoration of potential difference across the terminals of the battery (i.e. voltage source)
Answered by | 1st Mar, 2011, 10:20: AM
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