From a circular plate of diameter D, whose centre is C, another circular plate of diameter AC is cut, removed and kept over CB (in the given figure). The thickness of the plate is uniform. The shift of the centroid due to this operation will be
Consider the following statements : 1. Infiltration galleries are placed along the river beds at a depth of 4 to 6 m. 2. The draw-down for the infiltration galleries is more than that for radial wells. 3. Clogging of pipe pores in inflitration galleries is less than that for radial wells. 4. The cost of extracting unit volume of water is more in case of infiltration galleries as compared to radial wells. Which of the statements given above is/are correct ?