Section A
Q1.
(a)
Find out the pH of a mixture formed by mixing the following two water solutions :
Solution A : Volume 450 mL; pH = 7.5
Solution B : Volume 550 mL; pH = 6.5
(a) Compute the theoretical oxygen demand of 108.75 mg/l of glucose.
(b) (i) A rectangular plate of 0.5 m × 0.5 m dimensions, weighing 500 N slides down an inclined plane making 30° angle with the horizontal at a velocity of 1.75 m/s. If the 2 mm gap between the plate and inclined surface is filled with a lubricating oil, find its viscosity in poise.
(b) (ii) A channel has two sides vertical and semi-circular bottom of 2 m diameter. Calculate the discharge of water through the channel, when depth of flow is 2 m. Take C = 70 and slope of bed as 1 in 1000.
(c) A rectangular sewer with width twice its depth is hydraulically equivalent to a circular sewer. Find the relation between the width of the rectangular sewer and the diameter of the circular sewer assuming that sewer is running completely full.
(d)
After how many days will you supply water to soil (clay loam) in order to ensure efficient irrigation of the given crop, if :
Field capacity of soil = 27%
Permanent wilting point = 14%
Density of soil = 1.5 g/cm^3
Effective depth of root zone = 75 cm
Daily consumptive use of water for the given crop = 11 mm
(e) (i) A town with a population of 3 lakh produces solid waste at a rate of 2.5 kg/capita/day. If the waste is compacted to a density of 1500 kg/m^3, how much volume of landfill site is needed in a year? Assuming that the ratio of solid waste to cover is 4 : 1, what volume of cover soil is needed in a year? What type of soil would you recommend as a cover ?
