McqMate
| 101. |
In which unit operation, gases are released or absorbed in the water? |
| A. | gas transfer |
| B. | ion transfer |
| C. | solute stabilization |
| D. | solids transfer |
| Answer» A. gas transfer | |
| Explanation: in gas transfer, gases are released or absorbed in water by exposing the water through aeration under normal, increased or reduced pressure. | |
| 102. |
How many types of aerators are commonly used in the treatment of water? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» C. 4 | |
| Explanation: there are 4 types of aerators namely gravity aerators, spray aerators, diffusers and mechanical aerators. | |
| 103. |
Which of the following process is used to remove the colloidal particles from water? |
| A. | chemical precipitation |
| B. | chemical coagulation |
| C. | ion exchange |
| D. | adsorption |
| Answer» B. chemical coagulation | |
| Explanation: chemical coagulation is used to remove colloidal particles by the use of coagulants which increase the particle size and they settle down. | |
| 104. |
Flocculation of iron from water by the addition of lime is an example of which of the following process? |
| A. | chemical precipitation |
| B. | chemical coagulation |
| C. | ion exchange |
| D. | adsorption |
| Answer» A. chemical precipitation | |
| Explanation: chemical precipitation removes the dissolved substance from water through ion transfer where precipitation of dissolved impurities takes place. | |
| 105. |
In which unit operation objectionable solutes are converted into unobjectionable forms without removal? |
| A. | gas transfer |
| B. | ion transfer |
| C. | solute stabilization |
| D. | solids transfer |
| Answer» C. solute stabilization | |
| Explanation: in solute stabilization, water is stabilized by chlorination or liming so that objectionable solutes are converted into unobjectionable form. | |
| 106. |
In which form of solute stabilization, hydrogen sulfide in water is oxidized into sulfate? |
| A. | chlorination |
| B. | liming |
| C. | re-carbonation |
| D. | super-chlorination |
| Answer» A. chlorination | |
| Explanation: by the process of chlorination, water gets stabilized by the conversion of hydrogen sulfide into sulfate. | |
| 107. |
Which form of solute stabilization occurs when water passes through limestone? |
| A. | chlorination |
| B. | liming |
| C. | re-carbonation |
| D. | super-chlorination |
| Answer» B. liming | |
| Explanation: when water passes through limestone, carbon dioxide in excess get converted into soluble bicarbonate. | |
| 108. |
In which process, excess lime is converted into bicarbonate? |
| A. | chlorination |
| B. | liming |
| C. | re-carbonation |
| D. | super-chlorination |
| Answer» C. re-carbonation | |
| Explanation: by re-carbonation of water softened by excess lime treatment, excess lime is converted into bicarbonate. | |
| 109. |
By which process, odour producing substances is oxidized? |
| A. | chlorination |
| B. | liming |
| C. | re-carbonation |
| D. | super-chlorination |
| Answer» D. super-chlorination | |
| Explanation: by addition of chlorine dioxide to water, odour producing substances are oxidized. | |
| 110. |
Solids are removed from the water by which of the following unit operation? |
| A. | inter facial contact |
| B. | solid stabilization |
| C. | ion transfer |
| D. | solids transfer |
| Answer» D. solids transfer | |
| Explanation: during solids transfer, solids are removed from water by straining, sedimentation, flotation and filtration. | |
| 111. |
Dealkalization results in removal of all the ions from the water. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: dealkalization results in | |
| 112. |
Organic contaminants are removed from the water by the process of |
| A. | water softening |
| B. | demineralization |
| C. | absorption |
| D. | adsorption |
| Answer» D. adsorption | |
| Explanation: organic contaminants are removed from the water by the attraction and accumulation of one substance on the surface of another. | |
| 113. |
is an operation designed to force agitation in the fluid and induce coagulation. |
| A. | sedimentation |
| B. | flocculation |
| C. | disinfection |
| D. | aeration |
| Answer» B. flocculation | |
| Explanation: flocculation is an agitating process in which destabilized particles are brought into contact to promote agglomeration. | |
| 114. |
What is the dimension formula of mean velocity gradient? |
| A. | 1/t |
| B. | 1/t2 |
| C. | t |
| D. | t2 |
| Answer» A. 1/t | |
| Explanation: mean velocity gradient is expressed in metre per second/m or sec-1, so it has dimension formula of 1/t. | |
| 115. |
What is the normal value of the detention period adopted in a flocculator for design purpose? |
| A. | 30min |
| B. | 60min |
| C. | 90min |
| D. | 100min |
| Answer» A. 30min | |
| Explanation: the detention period in a flocculator for design purpose should be in the range of 10-40min and its normal value should be 30min. | |
| 116. |
The design value of the velocity of flow in a flocculator is |
| A. | 0.2-0.8m/s |
| B. | 0.3-0.5m/s |
| C. | 0.6-0.8m/s |
| D. | 0.1-0.5m/s |
| Answer» A. 0.2-0.8m/s | |
| Explanation: the normal value of the velocity of flow in a flocculator is 0.4m/s and its range is 0.2-0.8m/s. | |
| 117. |
What is the detention period of a clarifier used in the treatment of water? |
| A. | 1hour |
| B. | 2hours |
| C. | 3hours |
| D. | 4hours |
| Answer» C. 3hours | |
| Explanation: the detention period of a clarifier is lower than in the plain sedimentation tank and its range is 2.5 to 3 hours. | |
| 118. |
The pulsator clarifier is a type of |
| A. | horizontal flow sludge tank |
| B. | vertical flow sludge tank |
| C. | circular sludge tank |
| D. | plain sedimentation tank |
| Answer» B. vertical flow sludge tank | |
| Explanation: the pulsator clarifier is a vertical flow sludge tank in which pulse is generated at interval of 30sec to give rapid flow for 5-10sec resulting in the alternative rising up of the sludge blanket. | |
| 119. |
Which device solved the problem of unstable hydraulic conditions and operation of sludge removal equipment? |
| A. | centrifugal pump |
| B. | pulsator clarifier |
| C. | tube settler |
| D. | flocculator |
| Answer» C. tube settler | |
| Explanation: tube settler solved the problem of unstable hydraulic conditions and operation of sludge removal equipment by providing laminar flow conditions for sedimentation. | |
| 120. |
In which device, the primary mixing is followed by a secondary reaction zone resulting in formation of sludge blanket? |
| A. | centrifugal pump |
| B. | flocculator |
| C. | tube settler |
| D. | solid contact clarifier |
| Answer» D. solid contact clarifier | |
| Explanation: in solid contact clarifier, sludge blanket is formed where straining action occurs to remove some of the finer particles. the thickness of the blanket is 1m. | |
| 121. |
In which type of tube settler, tubes are slightly inclined in the direction of normal flow? |
| A. | solid contact clarifier |
| B. | steeply inclined tube settler |
| C. | vertical tube settler |
| D. | horizontal tube settler |
| Answer» D. horizontal tube settler | |
| Explanation: in horizontal tube settler, the tubes are slightly inclined in the direction of normal flow and the sludge settled is drained by filter backwash.they are used in small plants. | |
| 122. |
Ion exchange units are known as |
| A. | water hardeners |
| B. | water softeners |
| C. | water purifiers |
| D. | exchangers |
| Answer» B. water softeners | |
| Explanation: ion exchange units that replace calcium and magnesium ions from water are known as water softeners. they may also remove varying amounts of other inorganic pollutants such as metals. | |
| 123. |
Water softener units work most efficiently with particulate water. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: water softener units work most efficiently with particulate-free water. ion exchange units that replace calcium and magnesium ions from water are known as water softeners. | |
| 124. |
Which of these have a negative electrical charge? |
| A. | calcium |
| B. | magnesium |
| C. | sodium |
| D. | chloride |
| Answer» D. chloride | |
| Explanation: calcium and magnesium ions are atoms having a positive electrical charge, as do sodium and potassium ions. ions of the same charge can be exchanged. | |
| 125. |
The ions with opposite charge can be exchanged. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: ions of the same charge can be exchanged. in the process, the water containing calcium and magnesium ions is | |
| 126. |
While designing the demineralisation plant what is considered as the weak acidic cation load? |
| A. | alkaline hardness |
| B. | alkaline hardness+ ema |
| C. | ema |
| D. | silica |
| Answer» A. alkaline hardness | |
| Explanation: the load for weak acid cation is alkaline hardness alone. alkalinity is expressed as phenolphthalein alkalinity. it is also expressed as methyl orange alkalinity. | |
| 127. |
While designing the demineralisation plant what is considered as the strong acidic cation load? |
| A. | alkaline hardness |
| B. | alkaline hardness + ema |
| C. | ema |
| D. | silica |
| Answer» B. alkaline hardness + ema | |
| Explanation: the load for weak acid cation is alkaline hardness alone. this is also equivalent to total anions. total anions is equivalent to alkaline hardness + ema. | |
| 128. |
While designing the demineralisation plant what is considered as the strong basic anion load? |
| A. | alkaline hardness |
| B. | alkaline hardness + ema+co2 |
| C. | ema+silica |
| D. | silica+co2+ alkalinity+ema |
| Answer» D. silica+co2+ alkalinity+ema | |
| Explanation: the load for strong basic anion is silica+co2+ alkalinity+ema. this is in the case where there is no degasser. | |
| 129. |
While designing the demineralisation plant what is considered as the weak basic anion load? |
| A. | alkaline hardness |
| B. | alkaline hardness + ema |
| C. | ema |
| D. | silica |
| Answer» C. ema | |
| Explanation: the load for weak basic anion is ema alone. ema constitutes of chlorides, sulphides, nitrates etc. it is the sum total of these ions. | |
| 130. |
When is strong basic anion not necessary? |
| A. | silica is nil |
| B. | co2 is nil |
| C. | fluroine is nil |
| D. | sulphate is nil |
| Answer» A. silica is nil | |
| Explanation: when silica is nil, there is no requirement of a strong basic anion. degasser removes co2. a degasser tower is used in such cases. | |
| 131. |
When the hardness and alkalinity are around 30% what should be used? |
| A. | sac |
| B. | wac |
| C. | wac, sac |
| D. | wac, sac, wba |
| Answer» C. wac, sac | |
| Explanation: when the hardness and alkalinity are around 30%, then wac and sac should be used. wac removes temporary hardness caused by alkalinity. sac removes ema and alkalinity. | |
| 132. |
In case along with silica, there is high content in sulphide and chloride what should be used? |
| A. | wba |
| B. | wba and sba |
| C. | sba |
| D. | sba,wba and wac |
| Answer» B. wba and sba | |
| Explanation: in case the sulphide and chloride are present then wba should be used. sba removes only silica and alkalinity. it doesn’t remove ema. | |
| 133. |
What is the preferred regenerant in case of cation exchanger? |
| A. | hcl |
| B. | h2so4 |
| C. | h2co3 |
| D. | hf |
| Answer» A. hcl | |
| Explanation: the preffered regenerant in case of cation exchanger is hcl. | |
| 134. |
What is the preferred regenerant in case of anion exchanger? |
| A. | nacl |
| B. | naoh |
| C. | na2so4 |
| D. | na2co3 |
| Answer» B. naoh | |
| Explanation: the preffered regenerant in case of anion exchanger is naoh. regeneration is a process necessary to regenerate the resin. in this way the resin can be reused for the next demineralization process. | |
| 135. |
For obtaining Silica<5 ppm which of these should be utilized? |
| A. | sba followed by mixed be |
| B. | sba |
| C. | wba sba followed by mixed bed |
| D. | mixed bed |
| Answer» A. sba followed by mixed be | |
| Explanation: a mixed bed is usually followed after a sba to obtain silica level < 5 ppm. mixed bed constitutes both an anion and | |
| 136. |
In which year was the Ferrosand process patented? |
| A. | 1960 |
| B. | 1965 |
| C. | 1970 |
| D. | 1975 |
| Answer» B. 1965 | |
| Explanation: the manganese greensand process has been used in the united states since the 1950s. during the early years of its use, hungerford & terry, inc. of clayton, new jersey, worked to improve the process and eventually developed the ferrosand® cr process, patented in 1965. | |
| 137. |
What is the permitted concentration of manganese in drinking water? |
| A. | 30 g/l |
| B. | 40 g/l |
| C. | 50 g/l |
| D. | 60 g/l |
| Answer» C. 50 g/l | |
| Explanation: the permitted concentration of manganese in drinking water is 50g/l. the manganese greensand process has been used in the united states since the 1950s. | |
| 138. |
What is the permitted concentration of arsenic in drinking water? |
| A. | 10 g/l |
| B. | 20 g/l |
| C. | 30 g/l |
| D. | 40 g/l |
| Answer» A. 10 g/l | |
| Explanation: the permitted concentration of arsenic in drinking water is 10g/l. the permitted concentration of iron in drinking water is 200g/l. the permitted concentration of manganese in drinking water is 50g/l. | |
| 139. |
What is the minimum time of aeration? |
| A. | 20 minutes |
| B. | 40 minutes |
| C. | 60 minutes |
| D. | 80 minutes |
| Answer» C. 60 minutes | |
| Explanation: the water is aerated for a period of no less than 60 minutes. if water flow is 50 m3/h the aeration level is 100m3/h of air and tank volume is 50m3 of water. | |
| 140. |
What is the tank volume of aeration for water flow of 50m3/h? |
| A. | 40 m3 |
| B. | 50 m3 |
| C. | 80 m3 |
| D. | 100 m3 |
| Answer» B. 50 m3 | |
| Explanation: the water is aerated for a period of no less than 60 minutes. the tank volume of aeration for water flow of 50m3/h is 50 m3. | |
| 141. |
At what pH should the water be maintained? |
| A. | 6.5 |
| B. | 7.5 |
| C. | 8.5 |
| D. | 9 |
| Answer» B. 7.5 | |
| Explanation: the ph of the water should be increased to a value over ph 7.5. the decrease in the value of ph leads to increase in the acidity of water. | |
| 142. |
The aeration system will decrease the redox potential of the water. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: the aeration system will increase the redox potential of the water. it is important to raise the potential to as high a value as possible. certainly, it should be over 200mv. | |
| 143. |
What is the minimum required redox potential of water? |
| A. | 100 mv |
| B. | 200 mv |
| C. | 300 mv |
| D. | 400 mv |
| Answer» B. 200 mv | |
| Explanation: the minimum required redox potential of water is 200 mv. manganese oxidation requires a high oxidation potential. | |
| 144. |
Manganese oxidation requires a high oxidation potential. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: manganese oxidation requires a high oxidation potential, in some cases if there is a high bod or organic content in the water it may be required to add additional oxidizing agents such as hypochlorite, | |
| 145. |
What is the desirable bed depth for AFM filtration? |
| A. | 1000 mm |
| B. | 1200 mm |
| C. | 1500 mm |
| D. | 1800 mm |
| Answer» B. 1200 mm | |
| Explanation: the desirable bed depth of afm filtration is 1200 mm. maximum bed depth can be within 3000 mm and the bulk density is 1.25-1. | |
| 146. |
What is the maximum allowable flow for backwash? |
| A. | 20 m/hr |
| B. | 45 m/hr |
| C. | 60 m/hr |
| D. | 80 m/hr |
| Answer» C. 60 m/hr | |
| Explanation: the maximum allowable water flow for backwash is 60 m/hr. the recommended water flow for backwash is 45 m/hr. | |
| 147. |
The fluoride concentration for prevention of dental caries is |
| A. | 1mg/l |
| B. | 2mg/l |
| C. | 3mg/l |
| D. | 4mg/l |
| Answer» A. 1mg/l | |
| Explanation: dental caries occurs in children. it can be prevented when the | |
| 148. |
In which process, the fluoride content of water is raised? |
| A. | chlorination |
| B. | fluoridation |
| C. | defluoridation |
| D. | flocculation |
| Answer» B. fluoridation | |
| Explanation: when the fluoride content is low, it will cause dental caries. so the fluoride content of water is raised and the process is called fluoridation. | |
| 149. |
Which of the following is not used as a fluoride compound? |
| A. | sodium fluoride |
| B. | sodium silico fluoride |
| C. | hydrofluosilicic acid |
| D. | sodium fluro carbonate |
| Answer» D. sodium fluro carbonate | |
| Explanation: sodium fluoride, sodium silico fluoride, hydrofluosilicic acid and sodium fluro carbonate are the fluoride compounds used for fluoridation. | |
| 150. |
Which of the following is the pure compound? |
| A. | sodium fluoride |
| B. | sodium silico fluoride |
| C. | hydrofluosilicic acid |
| D. | sodium fluro carbonate |
| Answer» A. sodium fluoride | |
| Explanation: sodium fluoride is the most purest compound having 95-98% purity due to which, they are commonly used for fluoridation. | |
| 151. |
Fluorides in solution form are preferred over powdered form for fluoridation. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: fluorides in powdered form like sodium fluoride or sodium fluosilicate are toxic and must be contained in air tight containers. hence, they are not preferred. | |
| 152. |
What happens when water contains 8-20 ppm of fluoride concentration? |
| A. | blue baby disease |
| B. | crippling fluorosis |
| C. | dental fluorosis |
| D. | mottling of teeth |
| Answer» B. crippling fluorosis | |
| Explanation: dental fluorosis is caused when fluoride concentration is above 3 ppm, whereas crippling fluorosis is caused when the concentration of fluoride in water is between 8 and 20ppm. | |
| 153. |
The process of reducing the fluoride content from water is called |
| A. | chlorination |
| B. | fluoridation |
| C. | defluoridation |
| D. | flocculation |
| Answer» C. defluoridation | |
| Explanation: when the fluoride content in water is high, it is essential to reduce the fluoride content to avoid health related problems and the process of reducing the fluoride content is called defluoridation. | |
| 154. |
Which of the following is not used for defluoridation? |
| A. | calcium phosphate |
| B. | copper sulfate |
| C. | alum |
| D. | bone charcoal |
| Answer» B. copper sulfate | |
| Explanation: copper sulfate is used to remove taste, odor, color and control of algae growth and it is not used for fluoridation. | |
| 155. |
Which material is used in contact filters for the removal of fluorides? |
| A. | calcium phosphate |
| B. | copper sulfate |
| C. | synthetic tri-calcium phosphate |
| D. | bone charcoal |
| Answer» C. synthetic tri-calcium phosphate | |
| Explanation: synthetic tri-calcium phosphate is used in contact filters for the removal of fluorides. it is made from the milk of lime and phosphoric acid. | |
| 156. |
Which material is used for removing fluorides from hard water containing 3ppm of fluorides? |
| A. | lime |
| B. | copper sulfate |
| C. | synthetic tri-calcium phosphate |
| D. | bone charcoal |
| Answer» A. lime | |
| Explanation: lime is suitable for removing fluorides from hard water containing less than 4ppm. magnesium is also removed when this material is used for defluoridation. | |
| 157. |
Fluorex is a special mixture of |
| A. | di-calcium phosphate and carbon |
| B. | tri-calcium phosphate and hydroxyapatite |
| C. | di-calcium phosphate and phosphoric acid |
| D. | tri-calcium phosphate and carbon |
| Answer» B. tri-calcium phosphate and hydroxyapatite | |
| Explanation: fluorex is used for removing fluoride and it is a special mixture of tri- calcium phosphate and hydroxyapatite. it is used as a filter medium. | |
| 158. |
Which of the following is not a component of plumbing water supply system? |
| A. | washbasin |
| B. | water supply and distribution pipes |
| C. | valves |
| D. | storage tanks |
| Answer» A. washbasin | |
| Explanation: the plumbing system consists of the entire system of piping fixtures which are used for the supply and drainage of water. the various components of plumbing water supply system are water supply and distribution pipes, valves, storage tanks, etc. | |
| 159. |
Which of the following is not a component of the plumbing drainage system? |
| A. | water closets |
| B. | taps |
| C. | vent pipes |
| D. | urinals |
| Answer» B. taps | |
| Explanation: the different components of the plumbing drainage system are water closets, vent pipes, urinals, septic tanks, soil waste pipes, traps, etc. taps form the part of plumbing water supply system. | |
| 160. |
Light gauge copper tubes are used for general purpose work where the pressure is not more than 0.15 N/mm2. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: copper water service pipes are of two types. these are light gauge and heavy gauge. light gauge copper tubes are used for general purpose work where the pressure is not more than 0.15 n/mm2. | |
| 161. |
Which of the following is not true about lead pipes? |
| A. | lead pipes are highly resistant to corrosion |
| B. | they have a low hydraulic coefficient of flow |
| C. | lead pipes are highly flexible |
| D. | when lead goes into solution, it has a cumulative poisoning effect |
| Answer» B. they have a low hydraulic coefficient of flow | |
| Explanation: lead pipes have many advantages. they have a high hydraulic coefficient of flow and are highly resistant to corrosion. lead pipes are highly flexible. | |
| 162. |
Which of the following is not true about plastic pipes? |
| A. | plastic pipes are cheaper than the metal pipes |
| B. | plastic pipes are light in weight |
| C. | plastic pipes can be installed with ordinary tools |
| D. | plastic pipes are corrosive |
| Answer» D. plastic pipes are corrosive | |
| Explanation: plastic pipes are light in weight. ordinary tools are used to install plastic pipes. plastic pipes are non-corrosive and are cheaper than metal pipes. | |
| 163. |
is used to measure flows to domestic buildings. |
| A. | rain gauge |
| B. | water tank |
| C. | drainpipe |
| D. | water meter |
| Answer» D. water meter | |
| Explanation: water meter is used to measure flows to domestic buildings. a water meter should be easy to maintain and repair and it should measure and register both large and small flows accurately. | |
| 164. |
is used to measure the flow velocity across a cross-section with a known area. |
| A. | inferential meter |
| B. | anemometer |
| C. | speedometer |
| D. | barometer |
| Answer» A. inferential meter | |
| Explanation: there are generally two types of meters used in water distribution systems. these are inferential meter and displacement meter. the inferential meter is used to measure the flow velocity across a cross- section with a known area. | |
| 165. |
Inferential meters can be used for both low and high flows. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: inferential meters are used only for high flows. they are also known as velocity meters. for relatively low flows, displacement meters are used. | |
| 166. |
The method of distribution of water is divided into how many types? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| Explanation: the method of distribution of water is divided into 3 types and it includes gravity system, pumping system and combined gravity and pumping system. | |
| 167. |
In which of the following distribution system, the clean water flows entirely under gravity? |
| A. | gravity system |
| B. | pressure system |
| C. | combined gravity and pumping system |
| D. | pumping system |
| Answer» A. gravity system | |
| Explanation: the purified water in gravity system flow entirely under gravity. it is the most reliable and economical distribution system. | |
| 168. |
The pressure in the distribution mains does not depend on |
| A. | altitude to supply water |
| B. | fire fighting requirements |
| C. | availability of funds |
| D. | quality of water |
| Answer» D. quality of water | |
| Explanation: the pressure in the distribution mains depends on the height to which water is required to be supplied, fire fighting requirements, whether the supply is metered or not and availability of funds. | |
| 169. |
There is a 8 storey residential building in Lucknow. What is the pressure in the distribution mains? |
| A. | 2kg/cm2 |
| B. | 5kg/cm2 |
| C. | 7kg/cm2 |
| D. | 10kg/cm2 |
| Answer» B. 5kg/cm2 | |
| Explanation: when the height of residential building is between 6 to 10 storey, the pressure in the distribution mains lies between 4 to 5.5kg/cm2. | |
| 170. |
The velocity of water in a 10 cm diameter pipe should be |
| A. | 0.2m/sec |
| B. | 0.5m/sec |
| C. | 0.9m/sec |
| D. | 1.2m/sec |
| Answer» C. 0.9m/sec | |
| Explanation: the velocity of water in a 10 cm diameter pipe should be 0.9m/sec | |
| 171. |
In which system of water supply, water is available for 24 hours but uneconomically used? |
| A. | continuous supply |
| B. | fixed supply |
| C. | intermittent supply |
| D. | low supply |
| Answer» A. continuous supply | |
| Explanation: in continuous water supply, water is wasted due to a continuous supply of water for 24 hours of the day or long duration of flow. | |
| 172. |
In which system of water supply, water is supplied only during fixed hours of the day? |
| A. | continuous supply |
| B. | fixed supply |
| C. | intermittent supply |
| D. | low supply |
| Answer» C. intermittent supply | |
| Explanation: in intermittent supply, water is supplied to the consumer during fixed hours of the day and is adopted when sufficient pressure is not available or sufficient quantity of water is not available. | |
| 173. |
The velocity of water in the pipe is 1.8m/Sec. What is the diameter of pipe used? |
| A. | 10cm |
| B. | 15cm |
| C. | 25cm |
| D. | 40cm |
| Answer» D. 40cm | |
| Explanation: it is the maximum diameter of the pipe for which the velocity of water should not be less than 1.8m/sec. | |
| 174. |
The hourly demand rate is constant throughout the day. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: the hourly demand rate is not constant throughout the day, it is more during morning and evening and less during other parts of the day. | |
| 175. |
According the mass curve method, the storage capacity is defined as |
| A. | maximum excess of supply / maximum excess of demand |
| B. | maximum excess of supply * maximum excess of demand |
| C. | maximum excess of supply – maximum excess of demand |
| D. | maximum excess of supply + maximum excess of demand |
| Answer» D. maximum excess of supply + maximum excess of demand | |
| Explanation: a mass curve of demand is the cumulative demand curve, which is obtained by continuously adding the hourly demands and plotting it against time. | |
| 176. |
causes hoop tension in pipe shell. |
| A. | internal water pressure |
| B. | external water pressure |
| C. | water hammer |
| D. | longitudinal stress |
| Answer» A. internal water pressure | |
| Explanation: internal water pressure causes hoop tension in pipe shell and its magnitude is given by f = pd/2t where p is the internal pressure of water, d is the diameter of the pipe and t is the thickness of pipe shell. | |
| 177. |
The water supply pipes are buried underground. The load on the buried pipe due to earth filling is given by |
| A. | w = c*y*b |
| B. | w = c*y/b |
| C. | w = c*y*b2 |
| D. | w = c*y2*b |
| Answer» C. w = c*y*b2 | |
| Explanation: according to marston, the load w on buried pipes due to earth filling is given | |
| 178. |
Which of the following stress in pipe depends on temperature? |
| A. | internal water pressure |
| B. | stress due to foundation reaction |
| C. | longitudinal stress |
| D. | temperature stress |
| Answer» D. temperature stress | |
| Explanation: temperature stress is caused in pipes when they are laid above ground. when they are subjected to temperature variation, changes in the length of pipe takes place. | |
| 179. |
Pipe corrosion can be minimized by |
| A. | removal of copper sulfate |
| B. | addition of calcium carbonate |
| C. | addition of carbon dioxide |
| D. | removal of dissolved oxygen |
| Answer» D. removal of dissolved oxygen | |
| Explanation: pipe corrosion can be minimized by ph adjustment, control of calcium carbonate, removal of dissolved oxygen, removal of carbon dioxide and by the addition of sodium silicate. | |
| 180. |
How many types of pumps are present? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| Explanation: pumps are of two types. submersible pumps and open type pumps. submersible pumps require very less maintenance and are used inside water. both types can be used for traditional as well as hydro-pneumatic system. | |
| 181. |
Submersible pumps require high maintenance. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: submersible pumps require very less maintenance and are used inside water. both types can be used for traditional as well as hydro-pneumatic system. | |
| 182. |
What is the minimum diameter of pipes used for drainage of waste water? |
| A. | 50 mm |
| B. | 75 mm |
| C. | 100 mm |
| D. | 105 mm |
| Answer» B. 75 mm | |
| Explanation: waste water is from showers, basins, kitchen sinks, washing machines and the like. this is also called grey water. | |
| 183. |
What is the wastewater from kitchen sinks called? |
| A. | grey water |
| B. | black water |
| C. | yellow water |
| D. | brown water |
| Answer» A. grey water | |
| Explanation: normally a minimum of 75 mm diameter pipes are used for drainage of waste water. waste water is from showers, basins, kitchen sinks, washing machines and the like. this is also called grey water. | |
| 184. |
What is the water from urinals called? |
| A. | black water |
| B. | yellow water |
| C. | grey water |
| D. | brown water |
| Answer» A. black water | |
| Explanation: soil water or sewage is from wcs and urinals. this is also called black water. minimum of 100 mm diameter pipes are used for waste water. these can be of cast iron or of pvc. | |
| 185. |
What is the minimum diameter of the pipe used to collect black water? |
| A. | 50 mm |
| B. | 75 mm |
| C. | 100 mm |
| D. | 125 mm |
| Answer» C. 100 mm | |
| Explanation: soil water or sewage is from wcs and urinals. this is also called black water. minimum of 100 mm diameter pipes are used for waste water. | |
| 186. |
What is the recommended slope ratio for soil water pipes? |
| A. | 1:12 |
| B. | 1:20 |
| C. | 1:30 |
| D. | 1:40 |
| Answer» D. 1:40 | |
| Explanation: soil water pipes should run at a steeper slope, such as 1:40, as they have solids. these can be of cast iron or of pvc. minimum of 100 mm diameter pipes are used for waste water. | |
| 187. |
Grease should not be allowed to enter the normal drainage system. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: a grease trap should be used when draining waste from kitchens, grease | |
| 188. |
is used to clean blockage in the line. |
| A. | lateral chamber |
| B. | main chamber |
| C. | inspection chamber |
| D. | sewer chamber |
| Answer» C. inspection chamber | |
| Explanation: tone ware (ceramic) pipes are used when soil and waste water is to be transported in external soil. an inspection chamber is used to clean blockage in the line and change direction of pipes. | |
| 189. |
What is the shape of the septic tank? |
| A. | square |
| B. | rectangle |
| C. | circular |
| D. | oval |
| Answer» B. rectangle | |
| Explanation: a septic tank is a rectangular underground tank with compartments. it is always full of sewage that can be removed manually. the less water put into a septic tank, the better it will function. | |
| 190. |
What is the percentage of purification of septic tank effluent? |
| A. | 30% |
| B. | 50% |
| C. | 70% |
| D. | 90% |
| Answer» C. 70% | |
| Explanation: the effluent that flows out of this, which is about 70% purified, is then put into a soak pit. a soak pit is a cylindrical tank with porous brick walls surrounded by a layer of gravel. | |
| 191. |
should not be placed near water body. |
| A. | power generator |
| B. | soak pit |
| C. | pump stations |
| D. | houses |
| Answer» B. soak pit | |
| Explanation: a soak pit should not be placed | |
Done Reading?