Correct Answer : 2 to 3 ppm
Explanation : Ozone easily breaks down with oxygen and releases nascent oxygen which is powerful in killing bacteria. It also reduces organic matter present in the water the dosage of ozone is about 2 to 3 ppm.
Correct Answer : Option (B) : Outlets
Explanation : An outlet is a simple and small irrigation structure which is constructed along the distributaries. The amount of water that is withdrawn through the outlet is in proportion to the area that is irrigated below respective point.
Correct Answer : Option (A) : 2.5:1
Explanation : According to Terazghi, the following upstream slopes should be recommended.1. Homogeneous well graded – 2.5 : 12. Homogeneous coarse silt – 3 : 13. Sand and gravel with RCC core wall – 2.5 : 1.
Correct Answer : Option (A) : 0.25 to 5 cumecs
Explanation : The major distributary takes off from a branch canal to distribute the water to various parts of the field. The supply of the water varies from 0.25 to 5 cumecs.