The regulation formula of an alternator is represented by ______.
1
\({V_{NL}-V_{FL} \over V_{NL}} \times 100\)
2
\(\sqrt{(V Cos \theta +IR)^2 + (VSin\theta +IX_L)^2}\)
3
\({V_{NL}-V_{FL} \over V_{FL}} \times 100\)
4
\({V_{FL}-V_{NL} \over V_{NL}} \times 100\)