Question 413Electricity & Electronics - QMED

The correct answer is B) voltmeter. To determine the state of charge of a nickel-cadmium battery, a voltmeter is the appropriate tool to use. Nickel-cadmium batteries have a relatively flat discharge curve, meaning the voltage remains relatively constant until the battery is nearly depleted. By measuring the battery's terminal voltage with a voltmeter, you can assess its state of charge and determine if it needs to be recharged. The other options are incorrect because: A) an ammeter measures current, not state of charge; C) a hydrometer is used for lead-acid batteries, not nickel-cadmium; and D) a potentiometer is a general-purpose voltage measuring device, not specifically for determining battery state of charge.