Why determine/what is the importance of finding the phase shift between voltage and current?
The phase shift is very important in engineering. When there is a 90 degree difference, you can have a large current flowing but it isn’t transferring any net energy; energy is simply being alternately stored and released in the inductor (or capacitor), as in your experiment. Electrical supply engineers hate “inductive loads” for that reason, because they’d have to design their systems to carry a large current for little energy transfer. Therefore, electrical equipment often requires “power factor correction”, to reduce the phase difference to close to zero.
