What is the uncertainty in voltage measured by the multimeter?

There are several sources of uncertainty in voltage measurement by a multimeter, which include:

1. Accuracy of the multimeter: Each multimeter has a specified accuracy, which is usually expressed as a percentage of the full-scale reading. For example, a multimeter with an accuracy of +/- 1% may have an uncertainty of 0.1V when measuring a voltage of 10V.

2. Noise: The voltage measurement may be affected by the noise in the electrical circuit. This noise can come from various sources, such as electromagnetic interference, power supply noise, or thermal noise.

3. Input impedance: The multimeter's input impedance can also contribute to the uncertainty in voltage measurement. The input impedance is the resistance that the multimeter presents to the circuit being measured. A low input impedance can load the circuit and affect the voltage measurement accuracy.

4. Temperature: Temperature changes can affect the resistance of the multimeter's internal components, which can in turn affect the accuracy of the voltage measurement.

Overall, the uncertainty in voltage measurement by a multimeter depends on the accuracy and precision of the instrument, the electrical characteristics of the circuit being measured, and the environmental conditions. It is important to use the appropriate multimeter and measurement techniques to minimize the uncertainty in voltage measurement.