ANS:A - 2/g m of water

The term "2/g m of water" refers to a unit of measurement used to express head loss in fluid mechanics. It represents the head loss in terms of the height of a column of water that would produce the same pressure as the head loss. In this context, "g" represents the acceleration due to gravity (approximately 9.81 m/s²). When we divide 2 by the acceleration due to gravity (g), we get the time it takes for an object to fall freely under the influence of gravity from rest (neglecting air resistance), which is approximately 0.204 seconds. The term "m of water" indicates the equivalent height of a column of water that would produce the same pressure as the head loss. It is a convenient unit often used in fluid mechanics. Therefore, "2/g m of water" represents the head loss that would produce a pressure equivalent to the pressure exerted by a column of water of height 2/g meters. It's a way to standardize and quantify head loss in terms of water pressure.