Unity power factor (capacitance)

[suspenc3]

I have an assignment question with a variable capacitor in it and it asks what value of capacitance is necessary to provide "unity power factor overall". This wasnt explained in class, does anyone know what it means?

 

[interested_learner]

See: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/powfac.html

 

[Number2Pencil]

Do you now about real power, reactive power, and apparent power?