AC dimmer- triggering triac using moc3041. lamp always remain on, and does not change its intensity
From the schematic, I see that you "reversed" triac T1. Either turn it over or put gate lead between R8 and opto-coupler lead MT1 (on schematic).







simulate this circuit &ndash; Schematic created using CircuitLab

2) Need of R7 is to limit gate current of the triac.

3) Yes.