Q1: If H is height of the liquid above the sill, the effect of end contractions, according to Francis formula, is

ANS:A - 0.1 H

According to Francis' formula, the effect of end contractions can be represented by a contraction coefficient Cc​ which is applied to the theoretical velocity head (V^2​/2g) to calculate the actual velocity head. The contraction coefficient accounts for the reduction in effective cross-sectional area due to end contractions. In Francis' formula, the contraction coefficient Cc​ is given as: Cc​=0.1+​0.2/f​ Where F is the Froude number, given by V/gD​​, where V is the velocity, g is the acceleration due to gravity, and D is the depth of flow. In the case of a rectangular weir, the contraction coefficient is primarily dependent on the ratio of the width of the weir to the width of the channel. Assuming we are dealing with a rectangular weir, the end contractions are generally considered to be approximately 0.1 times the height of the liquid above the sill. Therefore, the effect of end contractions, according to Francis' formula, is typically around 0.1 H (where H is the height of the liquid above the sill).