When reading a measurement from an analog instrument like a ruler or a mercury thermometer, how should you determine the number of significant figures to record?

Answer and Explanation:

An analog instrument is one which provides the output which varies with time on a continuous basis or we can say that the output obtained from such instrument is a continuous function of time. This includes the instruments like ammeter, voltmeter, etc.

Significant figures in a measurement determines the degree of precision of a measurement or how the readings recorded are close to each other or how precise the measurement is.

Thus in order to determine the number of significant figures in a measurement recorded the figure of least significance is evaluated by reading in between the instrument's smallest markings.