Q1: When water flows over a rectangular suppressed weir, the negative pressure created beneath the nappe

ANS:A - increases the discharge

When water flows over a rectangular suppressed weir, the negative pressure created beneath the nappe increases the discharge. In a suppressed weir, the weir plate or crest is placed below the water surface, causing the water to flow freely over the weir without creating a distinct hydraulic jump downstream. As the water flows over the weir, a partial vacuum or negative pressure region forms beneath the nappe (the sheet of flowing water). This negative pressure beneath the nappe effectively helps to draw more water over the weir, increasing the discharge compared to what would be achieved with a weir in which the crest is fully exposed to atmospheric pressure. Therefore, the negative pressure created beneath the nappe in a suppressed weir increases the discharge.