Question: Tri-sodium phosphate is used in boiler water treatment to reduce____________________?

• 1. Turbidity
• 2. Caustic embrittlement
• 3. Suspended silica
• 4. Dissolved oxygen

Question: Moist atmospheric air at high temperature (e.g., in summer) having high concentration of sulphur dioxide causes________________?

• 1. Fading of dyes on textiles
• 2. Corrosion, tarnishing & soiling of metals
• 3. Reduced strength of textiles
• 4. All A, B & C

Question: Which of the following acts as a natural source of air pollution ?

• 1. Forest fire
• 2. Deforestation
• 3. Volcanic eruption
• 4. None of these

Question: Exposure to small amount of ______________ results in high blood pressure & heart disease in human beings?

• 1. Hydrogen sulphide
• 2. Mercury
• 3. Cadmium
• 4. Asbestos

Question: Noise level during normal conversation among men is about ______________ decibels?

• 1. 10
• 2. 45
• 3. 90
• 4. 115

Question: Ionisation potential employed in the industrial electrostatic precipitator is of the order of_______________?

• 1. 30 to 70 kV DC
• 2. 30 to 70 kV AC
• 3. 230 V AC
• 4. 230 V DC

Question: Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by_______________?

• 1. Chlorination
• 2. Treating in biological oxygen pond
• 3. Chemical coagulation
• 4. None of these

Question: Industrial workers working in leather tanning & manufacturing units are prone to suffer from ___________________?

• 1. Respiratory ailments (e.g. bronchitis)
• 2. Skin diseases (e.g. dermatitis)
• 3. Silicosis
• 4. Blurred vision

Question: ____________ substances present in sewage are removed in grit chamber during sewage treatment?

• 1. Organic
• 2. Fatty
• 3. Inorganic
• 4. Dissolved

Question: Maximum allowable concentration of CO2 in air for safe working is _____________ ppm (parts per million)?

• 1. 50
• 2. 1000
• 3. 2000
• 4. 5000