Multiple choice question for engineering
Set 1
1. Which type of bacteria has a rod shaped structure?
a) Bacilli
b) Cocci
c) Spirilla
d) Vibrio
Answer
Answer: a [Reason:] Bacilli (Singular-Bacillus) has a rod shaped structure. Cocci has a spherically shaped structure, Spirilla has a spiral shaped structure and Vibrio has a comma shaped structure.
2. ________ represents the bacterial density that is most likely to be present in water.
a) BOD
b) COD
c) MPN
d) Coliform index
Answer
Answer: c [Reason:] Most Probable Number is a number that indicates the bacterial density present in water.BOD and COD are the terms related to the oxygen required by microorganism to oxidize organic and inorganic matter.
3. Which of the following is a better test to identify Coliforms?
a) Coliform index
b) Multiple tube fermentation
c) MPN test
d) Membrane filter technique
Answer
Answer: d [Reason:] Membrane filter technique is a better and simpler technique to identify Coliforms. Various results are obtained in a shorter time than multiple tube fermentation technique. MPN test and coliform index are not used now.
4. What is the temperature at which MPN test is performed?
a) 35oC
b) 37 oC
c) 40oC
d) 45 oC
Answer
Answer: b [Reason:] MPN test is performed at 37oC where different samples of water are mixed with lactose broth and incubated in test tubes for 48 hours.
5.Which of the following statement is/are correct regarding coliform bacteria?
1. It is gram negative
2. It is rod shaped bacteria
3. It is a harmless aerobic microorganism
a) 1, 2, 3
b) 2, 3
c) 1, 3
d) 1,2
Answer
Answer: a [Reason:] Coliform bacteria is a gram negative, rod shaped and harmless aerobic microorganism which is found in the intestine of warm blooded animals including human beings.
6. Which of the following is the disease caused by bacterial infections?
a) Amoebic dysentery
b) Infectious hepatitis
c) Typhoid fever
d) Poliomyelitis
Answer
Answer: c [Reason:] Amoebic dysentery is caused by protozoan infection, Infectious hepatitis and Poliomyelitis are caused by a viral infection and Typhoid fever is caused by bacterial infection.
7. The number of bacterial colonies by Agar plate count test should not exceed ____ per ml for potable water.
a) 1
b) 10
c) 100
d) 1000
Answer
Answer: c [Reason:] Agar plate count test is a test to count the number of bacterial colonies growing on a specified medium and the permissible limit for the number of bacterial colonies is 100 per ml.
8. If the acid and gas are formed in the multiple tube fermentation technique, the test is _____
a) Positive
b) Continued
c) Negative
d) Discarded
Answer
Answer: a [Reason:] The acid and gas formation in Multiple tube fermentation technique indicates that the test is positive and there is coliform bacteria in the sample.
9. Which bacteria cause the reddish brown deposits in the tank?
a) Escherichia coli bacteria
b) Bacterium coli bacteria
c) Iron bacteria
d) Sulphur bacteria
Answer
Answer: c [Reason:] The growth of Iron bacteria causes the discoloration of tank due to reddish brown deposits and turbidity in water.
10. Which bacteria results in the corrosion of iron and steel pipes embedded in soil?
a) Escherichia coli bacteria
b) Bacterium coli bacteria
c) Iron bacteria
d) Sulphur bacteria
Answer
Answer: d [Reason:] Sulphur bacteria cause the corrosion of iron and steel pipes embedded in soil. They are both aerobic and anaerobic and are more destructive in marshy or clay soils where anaerobic conditions prevails.
11. State whether the following statement is True or False.
Gelatin liquefying bacteria are helpful in the manufacturing of photographic films.
a) True
b) False
Answer
Answer: a [Reason:] These bacteria are capable of producing proteolytic ferments which digest and liquefy gelatin. So, their presence in water is helpful in photographic films and glue industries.
Set 2
1. Which of the following is an end product formed from both the aerobic and anaerobic decomposition of organic matter?
a) NO3
b) CH4
c) H2S
d) CO2
Answer
Answer: d [Reason:] Carbon dioxide is formed due to the oxidation and reduction of organic matter by aerobic and anaerobic bacteria respectively.
2. The aerobic decomposition of carbonaceous organic matter gives
a) Nitrites and water
b) Carbon dioxide and water
c) Sulfates and water
d) Nitrogen and Ammonia
Answer
Answer: b [Reason:] Carbonaceous organic matter (oxidation by aerobic bacteria) —–> CO2 + H2O + Energy.
3. State whether the following statement is true or false.
BOD of wastewater having aerobic oxidation is more than that, having anaerobic oxidation.
a) True
b) False
Answer
Answer: b [Reason:] The BOD of wastewater where oxidation of organic matter takes place is very less in comparison to that formed by anaerobic oxidation, where BOD of 5000ppm can be formed.
4. The aerobic decomposition of nitrogenous organic matter gives
a) Nitrites and water
b) Carbon dioxide and water
c) Nitrates and ammonia
d) Nitrogen and ammonia
Answer
Answer: c [Reason:] Nitrogenous organic matter (oxidation by aerobic bacteria) —–> NO–3 + NH3 + Energy.
5. Methane is formed due to the reduction of
a) Nitrates
b) Sulfates
c) Carbon dioxide
d) Organic acids
Answer
Answer: d [Reason:] Organic acids (oxidation by anaerobic bacteria) —–> CH4 + CO2 + Energy.
6. Which of the following is formed due to the anaerobic decomposition of carbonaceous organic matter?
a) Nitrites
b) Carbon dioxide
c) Water
d) Nitrogen
Answer
Answer: b [Reason:] Carbonaceous organic matter (reduction by anaerobic bacteria) —–> CO2 + Energy.
7. Which of the following is formed due to the reduction of sulfurous organic matter?
a) Hydrogen sulfide
b) Hydrochloric acid
c) Sulfuric acid
d) Sulfur dioxide
Answer
Answer: a [Reason:] Sulfurous organic matter (reduction by anaerobic bacteria) —–> H2S + Energy.
8. Partially oxidized sewage contains
a) Nitrites and Nitrates
b) Nitrates and sulfur
c) Sulfates and nitrates
d) Nitrites and sulfur
Answer
Answer: d [Reason:] Partially oxidized sewage contains nitrites and sulfur whereas fully oxidized sewage contains nitrates and sulfates.
9. The aerobic decomposition of sulfurous organic matter gives
a) Nitrites and water
b) Carbon dioxide and water
c) Sulfates and water
d) Nitrogen and Ammonia
Answer
Answer: c [Reason:] Sulfurous organic matter (oxidation by aerobic bacteria) —–> SO–4 + Energy.
10. The energy released during the aerobic oxidation of organic matter is _____ kilo calories.
a) 26
b) 254
c) 360
d) 484
Answer
Answer: d [Reason:] Large amount of energy is released during the oxidation of organic matter with a magnitude between 484 and 674 kilo calories.
11. The decomposition of nitrogenous organic matter in the absence of oxygen gives
a) Nitrites and water
b) Carbon dioxide and water
c) Nitrates and ammonia
d) Nitrogen, ammonia and organic acids
Answer
Answer: d [Reason:] Nitrogenous organic matter (reduction by anaerobic bacteria) —–> N2 + NH3 + organic acids + Energy.
12. Which of the following is formed from the anaerobic oxidation of organic matter?
a) NO3
b) SO4
c) H2S
d) NH2
Answer
Answer: c [Reason:] H2S is formed from the anaerobic oxidation of sulfurous organic matter.
13. The number of stages required for the completion of aerobic oxidation is
a) 1
b) 2
c) 3
d) 4
Answer
Answer: a [Reason:] Aerobic oxidation gets completed only in single step, whereas anaerobic oxidation gets completed in two steps.
14. Which of the following is formed from oxidation of organic matter in the presence of oxygen?
a) NO3
b) SO4
c) H2S
d) NH2
Answer
Answer: a [Reason:] NO3 is formed due to the aerobic decomposition of nitrogenous organic matter.
15. The energy released during the anaerobic oxidation of organic matter is _____ kilo calories.
a) 26
b) 254
c) 360
d) 484
Answer
Answer: a [Reason:] Small amount of energy is released during the anaerobic oxidation in comparison to aerobic oxidation of organic matter with a magnitude of 26 kilo calories.
Set 3
1. ______ zone lies between Euphotic and Benthic zone.
a) Euphotic zone
b) Benthic zone
c) Littoral zone
d) Climate zone
Answer
Answer: c [Reason:] Littoral zone lies between Euphotic and Benthic zone. The growth of aquatic plants takes place in this zone.
2. The uppermost zone in lakes is called as
a) Euphotic zone
b) Benthic zone
c) Littoral zone
d) Climate zone
Answer
Answer: a [Reason:] The uppermost zone in lakes is called as Euphotic zone where sunlight passes through the lake and growth of plants takes place.
3. _______ is the process of overgrowth of plants and algae in lakes.
a) Transpiration
b) Reproduction
c) Eutrophication
d) Photosynthesis
Answer
Answer: c [Reason:] The process of overgrowth of plants and algae in lakes is called Eutrophication. It decreases the oxygen concentration of water.
4. Which of the following promotes eutrophication of lakes?
a) Magnesium
b) Sodium
c) Calcium
d) Phosphorous
Answer
Answer: d [Reason:] Phosphorous promotes the eutrophication of lakes as it is helpful for the growth of plants in lakes. It can easily reach the lakes through industrial water.
5. In which zone, decomposition of the dead organism takes place?
a) Climate zone
b) Benthic zone
c) Littoral zone
d) Euphotic zone
Answer
Answer: b [Reason:] In Benthic zone, the dead organism settled down where their decomposition takes place by the bacteria.
6. Which one of the following lakes has minimum productivity?
a) Mesotrophic lake
b) Senescent lake
c) Oligotrophic lake
d) Eutrophic lake
Answer
Answer: c [Reason:] Oligotrophic lake has a minimum productivity due to the presence of low phosphorous, nitrogen and other nutrients in the lake.
7. ________ is the process of acceleration of eutrophication due to increased phosphorous content in lakes.
a) Photosynthesis
b) Chemical eutrophication
c) Cultural eutrophication
d) Custom eutrophication
Answer
Answer: c [Reason:] Cultural eutrophication is the acceleration of eutrophication due to excessive nutrients in the water. It results in the death of aquatic plants and animals.
8. State whether the following statement is true or false.
The eutrophication process leads to turbidity in lakes.
a) True
b) False
Answer
Answer: a [Reason:] The eutrophication process causes the algal bloom which results in the milkiness in water causing turbidity.
9. Which type of pollution is a Cultural eutrophication?
a) Water pollution
b) Noise pollution
c) Thermal pollution
d) Soil pollution
Answer
Answer: a [Reason:] Cultural eutrophication is a water pollution due to the presence of excessive nutrients from house waste, industries, etc. that pollutes the lake, decreases the oxygen level and destroys the aquatic ecosystem.
10. The lakes are classified into how many types on the basis of productivity?
a) 2
b) 3
c) 4
d) 6
Answer
Answer: c [Reason:] The lakes are classified into 4 types on the basis of productivity, namely Senescent, Oligotrophic, Eutrophic and Mesotrophic.
11. The depth of Euphotic zone is measured by
a) Calorimeter
b) Turbidity meter
c) Secchi disk
d) Radar
Answer
Answer: c [Reason:] The depth of Euphotic zone is measured by Secchi disk where it is put in the lake and the depth at which the disk becomes invisible is taken as the depth of Euphotic zone.
Set 4
1. _______ is the velocity at which the solid matter in sewage remained in suspended form.
a) Settling velocity
b) Self cleansing velocity
c) Mean velocity
d) Non Scouring velocity
Answer
Answer: b [Reason:] Self cleansing velocity is the minimum velocity, which is required to keep the solid particles in suspended form otherwise they will settle and result in clogging.
2. The expression for the self cleansing velocity is given by
a) (8*B* (G-1) *g*d/f) 1/3
b) (8*B* (G-1) *g*d/f) 2
c) (8*B* (G-1) *g*d/f)
d) (8*B* (G-1) *g*d/f) 1/2
Answer
Answer: d [Reason:] The self cleansing velocity V is given by V = (8*B* (G-1) *g*d/f) 1/2 Where, G is the specific gravity, g is the acceleration due to gravity, d is the diameter of sewer and f is the Darcy Weisbach friction factor.
3. The self cleansing velocity required for coarse sand is
a) 10cm/Sec
b) 20cm/Sec
c) 30cm/Sec
d) 40cm/Sec
Answer
Answer: b [Reason:] The self cleansing velocity required for coarse sand is 20cm/Sec which is higher than fine sand having 15cm/Sec.
4. In which of the following, the self cleansing velocity is maximum?
a) Angular stones
b) Fine sand
c) Fine clay
d) Fine gravel
Answer
Answer: a [Reason:] The self cleansing velocity for angular stones is 100cm/Sec while of fine sand, fine clay and fine gravel are 15cm/Sec, 7.5cm/Sec and 30cm/Sec respectively.
5. The diameter of the sewer is 23cm. What should be the self cleansing velocity?
a) 10cm/Sec
b) 40cm/Sec
c) 100cm/Sec
d) 130cm/Sec
Answer
Answer: c [Reason:] When the diameter of the sewer is between 15cm and 25cm, the self cleansing velocity is 100cm/Sec.
6. What should be the diameter of the sewer when the self cleansing velocity is 60cm/Sec?
a) 10cm
b) 20cm
c) >60cm
d)100cm
Answer
Answer: c [Reason:] The self cleansing velocity varies inversely with the diameter of the sewer and when the diameter is above 60, the self cleansing velocity is 60cm/Sec whereas, for 15cm diameter of the sewer, it is 100cm/Sec.
7. The maximum velocity at which no abrasion takes place is called _______
a) Settling velocity
b) Self cleansing velocity
c) Mean velocity
d) Non Scouring velocity
Answer
Answer: d [Reason:] The non scouring velocity is the maximum velocity at which no scouring action takes place. It depends on the material used in the construction of sewers.
8. The non scouring velocity is 260cm/Sec. The type of material of the sewer is
a) Earth channels
b) Stone ware sewers
c) Brick lined sewer
d) Cement concrete sewer
Answer
Answer: d [Reason:] The non scouring velocity for cement concrete sewer lies between 250cm/Sec to 300 cm/Sec.
9. The non scouring velocity required for cast iron sewer pipes is
a) 50cm/Sec
b) 350cm/Sec
c) 160cm/Sec
d) 220cm/Sec
Answer
Answer: b [Reason:] The non scoring velocity depends on the material sewer and it is higher for cast iron sewer pipe with a range of 350-450cm/Sec.
Set 5
1. The temperature of sewage increases. What will be the effect on the dissolved oxygen in sewage?
a) Remains constant
b) Increase
c) Decrease
d) No effect
Answer
Answer: c [Reason:] The temperature and dissolved oxygen are inversely proportional to each other.
2. What is the minimum quantity of dissolved oxygen that should be present in the treated sewage?
a) 6ppm
b) 4ppm
c) 1ppm
d) 10ppm
Answer
Answer: b [Reason:] At least, 4ppm of dissolved oxygen should be present in treating sewage otherwise, fishes will die due to lack of dissolved oxygen.
3. The presence of which of the following in sewage indicates nitrogen content before decomposition of sewage?
a) Nitrites
b) Nitrates
c) Free ammonia
d) Albuminoid nitrogen
Answer
Answer: d [Reason:] The presence of Albuminoid nitrogen in water indicates the decomposition of sewage has not taken place.It nitrogen is also called as organic nitrogen.
4. The presence of free ammonia in sewage represents
a) Air pollution
b) Old pollution
c) Recent pollution
d) Water pollution
Answer
Answer: c [Reason:] The presence of free ammonia in sewage represents recent pollution
Which can be removed from wastewater by the nitrification process.
5. Which chemical is used for the titration of waste water for finding its chloride content?
a) Potassium chloride
b) Sodium chloride
c) Potassium chromate
d) Potassium dichromate
Answer
Answer: c [Reason:] Potassium chromate is used for the titration of waste water with silver nitrate solution for finding the chloride content.
6. The type of solids which floats in sewage is
a) Suspended solids
b) Settleable solids
c) Dissolved solids
d) Total solids
Answer
Answer: a [Reason:] The suspended solids float in sewage. 1000kg of sewage contain 0.112 kg of suspended solids.
7. The presence of which of the following indicates old pollution?
a) Nitrates
b) Nitrites
c) H2S
d) Sulfates
Answer
Answer: d [Reason:] The presence of nitrates indicates the old pollution. It also means that the nitrogen is fully oxidized in sewage.
8. ________ is used to find the D.O content of sewage.
a) Winkler method
b) Chromatography
c) Kjeldahl method
d) Olfactometer
Answer
Answer: b [Reason:] Wrinkler method is used to find the D.O content of sewage where the D.O content is proportional to the titration of iodine with S2O32- solution.
9. The permissible dose of chloride in domestic sewage is
a) 120ppm
b) 10ppm
c) 1ppm
d) 250ppm
Answer
Answer: a [Reason:] Domestic sewage includes waste from kitchen, laundry, toilet, bathroom, etc., which contain higher amount of chloride content, so the permissible dose of 120ppm is kept for domestic sewage.
10. Imhoff cone is used to measure the _______
a) Suspended solids
b) Settleable solids
c) Dissolved solids
d) Total solids
Answer
Answer: b [Reason:] Imhoff cone is used to measure the settleable solids where wastewater is allowed to stand for a specific time, solids get settled down and the readings are taken through the graduations on the cone.
11. The decomposition of sewage takes place, causing a pungent smell. Which of the following causes the pungent smell?
a) CO2
b) H2SO4
c) HCL
d) H2S
Answer
Answer: d [Reason:] The decomposition of sewage leads to the formation of sulfur compound like H2S which produces a pungent smell.
12. Which of the following disease is caused due to lack of nitrates?
a) Diphtheria
b) Methemoglobinemia
c) Tuberculosis
d) Meningitis
Answer
Answer: b [Reason:] Methemoglobinemia is a disease caused due to lack of nitrates in the body where the concentration of methemoglobin in red blood cells becomes greater than 1%.
13. The maximum quantity of dissolved oxygen present in wastewater is called
a) Saturated dissolved oxygen
b) Maximum dissolved oxygen
c) Optimal dissolved oxygen
d) Peak dissolved oxygen
Answer
Answer: a [Reason:] At a given temperature, the maximum quantity of dissolved oxygen in sewage in wastewater is called saturated dissolved oxygen.
14. Identify the odd one of the following.
a) Fatty acids
b) Chlorides
c) Cellulose
d) Fats
Answer
Answer: b [Reason:] Chlorides are inorganic matter, whereas Fatty acids, Cellulose and Fats are organic matter.
15. State whether the following statement is true or false.
The fresh sewage is acidic in nature.
a) True
b) False
Answer
Answer: b [Reason:] The fresh sewage is alkaline, but after sometime, the production of acid takes place and the pH of sewage decreases.