Question

What Is Null Voltage?

Answer 1

Hint: In physics, a null is a location in a field where the field quantity is zero due to the total cancellation of two or more opposing quantities. The field might be scalar, vector, or tensor. Nulls in the polar patterns of microphones and antennas, as well as nulls generated by wave reflections, are common occurrences.

Complete answer:
The term "null voltage" refers to the absence of any voltage. Wheatstone bridge instruments, for example, require a zero reading, which is obtained using null voltage. In electrical science, nulls are used to accomplish a variety of measurements. Adjusting the voltage in one branch of a circuit until it nulls out a voltage in another branch is a common approach. A bridge circuit is commonly employed for this purpose. There are several different types of measurement bridges, the most well-known of which is the Wheatstone bridge, which is used to compare the voltages across each component to precisely measure the resistance of an unknown component against a calibrated variable resistance.
The voltage under test is on one side of the bridge's central branch, and the calibrated voltage is on the other; when they're equal, the voltage across the central branch is nulled out. The measurement is made by putting an instrument in the central branch to detect voltage or current. The bridge approach has the benefit of not requiring calibration because the instrument is only required to detect nulls and not to actually measure a voltage. The precision of the measurement will, however, be determined by the instrument's sensitivity, as this will impact the bridge's resolution.

Note:
In wind musical instruments, standing waves can be encountered. Standing waves are created in a tube that functions as an acoustic transmission line in wind instruments. The end of an open ended tube must have zero air pressure change, therefore this point is a pressure null. The end of a closed tube must have zero air velocity, therefore this point is a velocity null. Depending on the vibration mode selected by the instrument player, there may be additional nulls throughout the tube. There are more nulls in higher modes.