Effluent from an industry 'A' has a pH of 4.2. The effluent from another industry 'B' has double the hydroxyl (OH^-) ion concentration than the effluent from industry 'A'. pH of effluent from the industry 'B' will be _______.

A sector gate is provided on a spillway as shown in the figure. Assuming g = 10 m/s², the resultant force per meter length (expressed in kN/m) on the gate will be __________

The porosity (n) and the degree of saturation (S) of a soil sample are 0.7 and 40%, respectively. In a 100 $$m^3$$ volume of the soil, the volume (expressed in $$m^3$$) of air is _____.

A concrete gravity dam section is shown in the figure. Assuming unit weight of water as 10$$kN/m^3$$ and unit weight of concrete as 24$$kN/m^3$$, the uplift force per unit length of the dam (expressed in kN/m) at PQ is____.