The pH of normal rainwater is:

1.	6.0 to 7.0	2.	6.5 to 7.5
3.	5.6 to 6.5	4.	less than 5.5

The most effective device to remove particulate matter from polluted air is:
1. electrostatic precipitator

2. cyclonic separator

3. trajectory separator

4. scrubber

The device, normally used to remove gaseous pollutants from polluted air but can remove large particulate matter as well, is:
1. electrostatic precipitator

2. cyclonic separator

3. trajectory separator

4. Scrubber

Catalytic Converters:

1. only I & II are correct
2. only I & III are correct
3. Only II & III are correct
4. I, II & III are correct

A water body has low DO content. An organism that is likely to flourish here will be:
1. Gonyaulax, an annelid
2. Gonyaulax, a nematode
3. Tubifex, an annelid
4. Tubifex, a nematode

In an algal bloom, the cause of death of other algae is usually:
1. toxins

2. decreased DO

3. decreased sunlight

4. decreased nutrients

Identify the incorrectly matched pair with respect to contamination of water:
1. Minamata disease: Mercury
2. Blue bay syndrome: excessive nitrates
3. Black foot disease: excessive arsenic
4. Dental caries: excessive fluoride

A painful bone condition is produced when the drinking water is contaminated with:
1. Lead
2. Mercury
3. Cadmium
4. Arsenic

Combustion of solid wastes in the absence of oxygen is known as:

The intensity of noise beyond which physical discomfort is:
1. 70 dB
2. 80 dB
3. 100 dB
4. 120 dB