Motional EMF Video Lessons

Concept

# Problem: Consider an unknown dry cell for which a potentiometer is balanced when the variable resistance is Rx = 1.7 Ω, while an alkaline standard cell with an emf of 1.2 V requires RS = 1.25 Ω to balance the potentiometer.Randomized VariablesES = 1.2 VRX = 1.7 ΩRS = 1.25 ΩCalculate the emf of the dry cell, in volts

###### FREE Expert Solution

Consider the relation:

$\overline{){\mathbf{e}}{\mathbf{m}}{{\mathbf{f}}}_{{\mathbf{x}}}{\mathbf{=}}{\mathbf{e}}{\mathbf{m}}{{\mathbf{f}}}_{{\mathbf{s}}}\frac{{\mathbf{R}}_{\mathbf{x}}}{{\mathbf{R}}_{\mathbf{s}}}}$

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###### Problem Details

Consider an unknown dry cell for which a potentiometer is balanced when the variable resistance is Rx = 1.7 Ω, while an alkaline standard cell with an emf of 1.2 V requires RS = 1.25 Ω to balance the potentiometer.

Randomized Variables

ES = 1.2 V

RX = 1.7 Ω

RS = 1.25 Ω

Calculate the emf of the dry cell, in volts