1. Tolerable limit of nitrogen oxides in air is __________ ppm.
C. Cotton Fibers
3. In water chemical treatment plant, use of chloramines ensures
A. taste & odour control.
C. removal of permanent hardness.
D. weed control in reservoirs.
4. Turbidity of water is an indication of the presence of
A. floating solids
B. dissolved solids
C. suspended inorganic matter
D. dissolved gases
5. Particulates (< 1µm size) remaining suspended in air indefinitely and transported by wind currents are called
6. TLV (Threshold Limit Values) of mercury in potable (drinking) water is about __________ ppm.
7. During which of the following operating conditions of an automobile, carbon monoxide content in the exhaust gas is maximum ?
C. Idle running
8. Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air.
A. hydrogen sulphides
C. nitrogen dioxide
D. hydrogen fluoride
9. Presence of excess fluorine in water causes
A. respiratory disease
B. tooth decay
C. dental cavity
10. Iron & manganese present as pollutant in water can not be removed by
A. lime soda process or manganese zeolite process.
B. ion exchange process.
C. oxidation followed by settling & filtration.