Lets say if purchased 100 Rcom shares each 100/-. Lets say company decided to provide 4rs dividend to each share. After payout will all shares get adjusted to 96/- or continue at 100/-.
Yes, the stocks do get adjusted for splits. You can read more about dividends and other corporate actions here - http://zerodha.com/varsity/chapter/five-corporate-actions-and-its-impact-on-stock-prices/