Question : What causes the mottling of the dental enamel?

Option 1: High levels of chlorine in water

Option 2: High levels of nitrate in the water

Option 3: High levels of fluorides in the water

Option 4: High levels of calcium in the water

Question : In water treatment plants, the use of chloramines ensures _____________.

Option 1: taste and odour control

Option 2: weed control in reservoirs

Option 3: disinfection

Option 4: removal of permanent hardness

Question : The purest form of water is

Option 1: Tap water

Option 2: Rain water

Option 3: Ground water

Option 4: Distilled water

Question : Recharging of water table depends on

Option 1: amount of rainfall

Option 2: relief of the area

Option 3: vegetation of the area

Option 4: amount of percolation

Question : In a mixture of 25 litres, the ratio of milk to water is 4 : 1. Another 3 litres of water is added to the mixture. The ratio of milk to water in the new mixture is:

Option 1: 5 : 1

Option 2: 5 : 2

Option 3: 5 : 3

Option 4: 5 : 4