The limit to the precision of the potential measured by a null-point apparatus (as in Figure 2.1) is associated with the precision of the variable resistor used to adjust the voltage at point $A$. Precision variable resistors are commonly available with a rotary control that moves the sliding contact from the bottom position to the other extreme in 10 turns. Assuming that the dial on the rotary control can discriminate between settings that are $1^{\circ }$ apart and assuming that the voltage on the battery is $1.5000V$, what is the uncertainty in volts in the voltage provided at point $A$ ?

Figure 2.1 

Transcribed Image Text:

Battery Adjustable voltage source Current meter B Cell