Internal Resistance and EMF of a Cell

Question

Question:

While discharging, which is usually greater, the Terminal Potential Difference (TPD)/Terminal Voltage or electromotive force (emf)?

When can the reverse case of the question above be true?

^__^physics^__^

Answer 1

if you are drawing current, the terminal potential difference will be lower than the emf by an amount equal to the internal ohmic voltage drop across the cell.

Answer 2

The equation potential difference/terminal voltage is true because potential difference and emf and nearly the same

Answer 3

The equation potential difference/terminal voltage is true because potential difference and emf and nearly the same

Answer 4

Whenever you have a current flowing through a battery, you always have a potential drop across the battery's internal resistance.

If the battery is discharging, EMF = Terminal voltage + pd across internal resistance, so the TPD is always less than the EMF of the battery.

If the battery is being charged, Charging voltage = TPD = EMF + p.d. across internal resistance.  In this case, the TPD must be greater than the EMF of the battery.