In forward biasing the positive terminal of the battery is connected to the the p-side and the negative terminal to the n-side of the p-n junction. The forward bias voltage opposes the potential barrier. Due to this, the potential barrier is reduced and hence the depletion layer becomes thin. The conduction across p-n junction takes place due to migration of majority carriers from one region to another. The resistance of p-n junction becomes low when forward biased.