A portable chemistry probe contains a single non-ideal battery that supplies power to…
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A portable chemistry probe contains a single non-ideal battery that supplies power to various interchangeable sensors. When no sensor is attached, the voltmeter across the battery’s terminals reads 9.00 V. When a conductivity sensor is plugged in, the terminal potential difference immediately drops to 8.40 V even though the battery’s emf is unchanged.
Assume the battery’s internal resistance and the sensor’s resistance are both constant during the brief measurement interval.
(1) Explain qualitatively why the terminal potential difference decreases when the sensor is connected, even though the emf of the battery remains the same.
(2) Describe how the magnitude of the current through the battery compares in the open-circuit (no sensor) and loaded (sensor attached) cases.
(3) The manufacturer wants to minimize the difference between the open-circuit and loaded terminal voltages. Describe two practical modifications to the battery–sensor system that would achieve this goal, and explain the physical reasoning behind each modification.