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Question 1
ప్రశ్న 1
Which group consists predominantly of physical or organoleptic water-quality characteristics?
Explanation:
Physical and organoleptic examination deals with characteristics that affect the appearance, sensory acceptability and certain observable properties of water. Turbidity and colour are important physical characteristics, while taste and odour strongly affect consumer acceptability. Temperature also influences water quality by affecting reaction rates, taste and the solubility of gases. Nitrate, fluoride and hardness are primarily chemical characteristics, whereas E. coli is examined under bacteriological quality. Therefore Option A is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which statement best describes turbidity in water analysis?
Explanation:
Turbidity is caused by suspended and colloidal particles that scatter light passing through water. It is commonly measured in nephelometric turbidity units, abbreviated as NTU. High turbidity can interfere with disinfection because microorganisms may be shielded by particles. Turbidity does not directly measure pathogens, hardness or alkalinity. Therefore Option B is correct.
వివరణ:
Question 3
ప్రశ్న 3
What is the principal significance of temperature as a water-quality parameter?
Explanation:
Water temperature influences many physical, chemical and biological processes. Increasing temperature generally accelerates reaction and biological rates and can affect taste and odour perception. Gas solubility, including that of dissolved oxygen, generally decreases as water temperature increases. Temperature by itself does not measure chloride, hardness or bacteriological contamination. Therefore Option C is correct.
వివరణ:
Question 4
ప్రశ్న 4
A water sample has total solids of 900 mg/L and total dissolved solids of 650 mg/L. Assuming total solids are the sum of dissolved and suspended solids, what is the total suspended-solids concentration?
Explanation:
Total solids can be conceptually separated into total dissolved solids and total suspended solids. Therefore TSS = TS - TDS for the stated simplified calculation. Substituting the values gives 900 - 650 = 250 mg/L. Suspended solids are associated with particles retained by the relevant filtration procedure, whereas dissolved solids pass through it. Therefore Option B is correct.
వివరణ:
Question 5
ప్రశ్న 5
Which statement about pH is correct?
Explanation:
pH is a logarithmic measure related to hydrogen-ion activity and indicates whether water is acidic, neutral or alkaline in reaction. It describes intensity rather than the total capacity of water to neutralize acid or base. Two waters with similar pH can have very different alkalinity because their buffering capacities may differ. Alkalinity, acidity and hardness are normally reported as concentration-based parameters rather than as pH units. Therefore Option A is correct.
వివరణ:
Question 6
ప్రశ్న 6
According to the currently applicable IS 10500 drinking-water specification, what is the acceptable pH range for drinking water?
Explanation:
IS 10500 specifies an acceptable drinking-water pH range of 6.5 to 8.5. The standard provides no relaxation beyond this range in the absence of an alternate source. Very low or high pH can affect corrosion, treatment performance, taste and distribution-system behavior. pH compliance should therefore be evaluated separately from parameters for which a higher permissible value is specifically allowed. Therefore Option C is correct.
వివరణ:
Question 7
ప్రశ్న 7
What does alkalinity of water principally represent?
Explanation:
Alkalinity represents the capacity of water to neutralize added acid. In natural waters, bicarbonate is commonly the dominant contributor, although carbonate and hydroxide can also contribute. Alkalinity is conventionally expressed in mg/L as CaCO3 for engineering calculations and comparison. It is important in coagulation chemistry, corrosion control and buffering against rapid pH change. Therefore Option B is correct.
వివరణ:
Question 8
ప్రశ్న 8
Which statement most accurately describes acidity in water analysis?
Explanation:
Acidity is the quantitative capacity of water to react with and neutralize a base. Dissolved carbon dioxide, mineral acids and hydrolyzing acidic salts can contribute to acidity. Acidity is not the same as pH because pH measures hydrogen-ion intensity whereas acidity represents neutralizing capacity. Calcium bicarbonate is more commonly associated with alkalinity and temporary hardness rather than acidity. Therefore Option A is correct.
వివరణ:
Question 9
ప్రశ్న 9
Total hardness of natural water is principally associated with which dissolved ions?
Explanation:
Hardness in most natural waters is caused predominantly by dissolved calcium and magnesium salts. Other multivalent ions can contribute, but calcium and magnesium are normally the major engineering constituents. Hardness affects soap consumption and can lead to scale formation in pipes, boilers and heating systems. It is conventionally expressed as an equivalent concentration of CaCO3. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
Under IS 10500, what are the acceptable limit and permissible limit in the absence of an alternate source for total hardness expressed as CaCO3?
Explanation:
The acceptable limit for total hardness under IS 10500 is 200 mg/L as CaCO3. In the absence of an alternate source, the permissible limit is 600 mg/L as CaCO3. Hardness above the acceptable value can cause scaling and undesirable effects in domestic use, although it is not interpreted in the same way as a toxic contaminant. The acceptable and permissible values must therefore not be confused with the limits for TDS or chloride. Therefore Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
Which interpretation of chloride concentration in drinking water is most appropriate?
Explanation:
Chloride is a dissolved chemical constituent rather than a bacteriological parameter. Excessive chloride can impair taste and can increase the corrosive character of water under some conditions. IS 10500 specifies an acceptable chloride limit of 250 mg/L and a permissible limit of 1000 mg/L in the absence of an alternate source. Chloride is measured as a concentration, not in turbidity units. Therefore Option B is correct.
వివరణ:
Question 12
ప్రశ్న 12
Under IS 10500, what are the acceptable and permissible limits for sulphate in drinking water?
Explanation:
IS 10500 gives an acceptable sulphate concentration of 200 mg/L. The permissible value in the absence of an alternate source is 400 mg/L. Excessive sulphate can affect taste and may have laxative effects at sufficiently high concentrations, particularly in combination with some cations. These values should not be confused with nitrate, for which no higher permissible limit above 45 mg/L is provided. Therefore Option C is correct.
వివరణ:
Question 13
ప్రశ్న 13
A drinking-water sample contains nitrate as NO3 at 52 mg/L. How should this result be interpreted with respect to IS 10500?
Explanation:
IS 10500 specifies 45 mg/L as the maximum acceptable value for nitrate expressed as NO3. No higher permissible value is provided in the absence of an alternate source. A result of 52 mg/L therefore exceeds the applicable drinking-water requirement. Nitrate is a chemical water-quality parameter and must not be judged from TDS compliance alone. Therefore Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
Which pair correctly gives the IS 10500 acceptable and permissible fluoride limits for drinking water?
Explanation:
The acceptable fluoride concentration specified by IS 10500 is 1.0 mg/L. The permissible concentration in the absence of an alternate source is 1.5 mg/L. Fluoride has an important concentration-dependent health significance because excessive long-term intake can cause fluorosis. A concentration above 1.5 mg/L is therefore beyond the permissible drinking-water value under this standard. Therefore Option B is correct.
వివరణ:
Question 15
ప్రశ్న 15
After applying the amendments to IS 10500:2012, what is the acceptable maximum concentration of iron as Fe in drinking water?
Explanation:
The original 2012 table showed an iron value of 0.3 mg/L. Amendment No. 1 to IS 10500:2012 specifically substituted 1.0 mg/L for 0.3 mg/L in Table 2 for iron. The amended acceptable maximum is therefore 1.0 mg/L as Fe, with no higher relaxation in the absence of an alternate source. This is an important example of why current amendments must be checked instead of relying on an unamended textbook table. Therefore Option B is correct.
వివరణ:
Question 16
ప్రశ్న 16
According to IS 10500, what are the acceptable and permissible limits for turbidity in drinking water?
Explanation:
The acceptable turbidity limit under IS 10500 is 1 NTU. The permissible limit in the absence of an alternate source is 5 NTU. Low turbidity is important not only for appearance but also for efficient treatment and disinfection. High particulate loading can shelter microorganisms and increase disinfectant demand or treatment difficulty. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
A treated-water sample has TDS of 700 mg/L. Which interpretation is correct under IS 10500, considering TDS alone?
Explanation:
The acceptable TDS limit in IS 10500 is 500 mg/L. A value of 700 mg/L therefore exceeds the acceptable limit. However, the permissible limit in the absence of an alternate source is 2000 mg/L, so 700 mg/L remains below that value. This interpretation concerns TDS alone and does not establish overall potability unless all other applicable parameters also comply. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
Under the current bacteriological requirements applied with IS 10500, what is the requirement for E. coli in drinking water?
Explanation:
E. coli is a primary indicator of faecal contamination and its detection represents a serious microbiological concern. Under the current bacteriological requirement, E. coli shall not be detectable in any 100 mL sample of drinking water. Total coliforms are likewise required not to be detectable in any 100 mL sample under the amended bacteriological table. Chemical compliance cannot compensate for microbiological failure because pathogen transmission can present an immediate health risk. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
Which statement best distinguishes potable water from non-potable water?
Explanation:
Potability involves more than visual appearance or the origin of the water. Water intended for drinking must satisfy applicable physical, chemical and bacteriological requirements and be acceptable for consumption. Non-potable water may still be suitable for uses such as certain industrial, irrigation or flushing applications depending on its quality. Raw groundwater or clear surface water cannot be assumed potable without appropriate assessment. Therefore Option B is correct.
వివరణ:
Question 20
ప్రశ్న 20
What does the term raw water mean in a public water-supply system?
Explanation:
Raw water is source water before completion of the treatment required to make it suitable for the intended supply. It may originate from a river, reservoir, lake, spring or groundwater source. Its physical, chemical and microbiological quality determines the type and intensity of treatment required. Raw water is therefore not synonymous with sewage and should not automatically be classified as potable. Therefore Option A is correct.
వివరణ:
Question 21
ప్రశ్న 21
Under CPCB's designated-best-use classification of surface water, what does Class A represent?
Explanation:
CPCB Class A is a source-water classification under the designated-best-use system. It denotes surface water suitable as a drinking-water source without conventional treatment but after disinfection. CPCB criteria for this class include specified limits for total coliforms, pH, dissolved oxygen and BOD. The classification does not mean that untreated Class A river water is automatically identical to finished drinking water complying with IS 10500 at the consumer end. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
Under CPCB's designated-best-use surface-water classification, Class C water is intended for which use?
Explanation:
CPCB Class C denotes a drinking-water source requiring conventional treatment followed by disinfection. It therefore represents a different raw-water treatment requirement from Class A, which does not require conventional treatment before disinfection. CPCB Class C criteria include specified limits for total coliforms, pH, dissolved oxygen and BOD. The Class C designation must not be confused with a finished drinking-water quality category under IS 10500. Therefore Option A is correct.
వివరణ:
Question 23
ప్రశ్న 23
A raw surface water has high turbidity and significant bacteriological contamination but no unusual dissolved toxic contaminants. Which treatment concept is generally more appropriate than disinfection alone?
Explanation:
High raw-water turbidity indicates a substantial particulate and colloidal load. Disinfection alone may be unreliable because particles can shield microorganisms and consume disinfectant. Conventional treatment can remove much of the turbidity through coagulation, flocculation, clarification and filtration before final disinfection. Exact process selection must still be based on detailed raw-water analysis and treatability. Therefore Option A is correct.
వివరణ:
Question 24
ప్రశ్న 24
A treated-water sample has pH 7.4, turbidity 0.8 NTU, nitrate 52 mg/L and fluoride 1.1 mg/L. If permissible limits in the absence of an alternate source are applied wherever IS 10500 allows them, which parameter still clearly exceeds the applicable drinking-water limit?
Explanation:
A pH of 7.4 lies within the required range of 6.5 to 8.5. Turbidity of 0.8 NTU is below the acceptable maximum of 1 NTU. Fluoride at 1.1 mg/L exceeds the acceptable value of 1.0 mg/L but remains below the permissible value of 1.5 mg/L when the absence-of-alternate-source provision is applicable. Nitrate at 52 mg/L exceeds 45 mg/L, and IS 10500 provides no relaxation for nitrate. Therefore nitrate clearly exceeds the applicable limit and Option C is correct.
వివరణ:
Question 25
ప్రశ్న 25
Which statement best describes the engineering relationship between water analysis and treatment-process selection?
Explanation:
Treatment-process selection should respond to the actual quality problems present in the source water. High turbidity may require clarification and filtration, while specific dissolved contaminants can require specialized chemical or physical treatment. Microbiological risk requires effective disinfection and appropriate upstream particle removal. The required finished-water quality provides the performance target against which the treatment train is designed. Therefore Option B is correct.
వివరణ:
Question 26
ప్రశ్న 26
Consider the following statements: I. Turbidity and colour are principally physical or organoleptic characteristics. II. Hardness, nitrate and fluoride are chemical characteristics. III. E. coli is a bacteriological indicator of faecal contamination. IV. CPCB raw-water classes based on designated best use should not be confused with IS 10500 finished drinking-water requirements. Which option is correct?
Explanation:
Statement I correctly places turbidity and colour among the important physical or organoleptic characteristics of water. Statement II correctly identifies hardness, nitrate and fluoride as chemical water-quality parameters. Statement III is correct because E. coli is an important indicator of faecal contamination and must not be detectable in drinking water. Statement IV is essential because CPCB source-water classes describe designated use and treatment requirement, whereas IS 10500 specifies drinking-water quality requirements. Therefore all four statements are correct and Option D is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: A. Turbidity, colour, taste, odour and temperature సమాధానం: A.
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Question 2 ప్రశ్న 2Answer: B. It represents the cloudiness caused by fine suspended and colloidal matter and is commonly reported in NTU సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: C. It affects reaction rates, biological activity, taste and the solubility of gases such as oxygen సమాధానం: C.
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Question 4 ప్రశ్న 4Answer: B. 250 mg/L సమాధానం: B.
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Question 5 ప్రశ్న 5Answer: A. pH indicates the intensity of acidic or alkaline conditions but does not by itself quantify total acidity or alkalinity సమాధానం: A.
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Question 6 ప్రశ్న 6Answer: C. 6.5 to 8.5 సమాధానం: C.
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Question 7 ప్రశ్న 7Answer: B. The acid-neutralizing capacity of water, commonly associated with bicarbonate, carbonate and hydroxide species సమాధానం: B.
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Question 8 ప్రశ్న 8Answer: A. It represents the capacity of water to neutralize a strong base and may arise from carbon dioxide, mineral acids and acidic salts సమాధానం: A.
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Question 9 ప్రశ్న 9Answer: B. Calcium and magnesium సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: B. 200 and 600 mg/L సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: B. Excess chloride can adversely affect taste and may contribute to corrosive characteristics of water సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: C. 200 and 400 mg/L సమాధానం: C.
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Question 13 ప్రశ్న 13Answer: B. It exceeds the 45 mg/L limit, for which no relaxation is provided సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: B. 1.0 and 1.5 mg/L సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: B. 1.0 mg/L సమాధానం: B.
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Question 16 ప్రశ్న 16Answer: A. 1 NTU and 5 NTU సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: B. It exceeds the acceptable limit of 500 mg/L but remains below the 2000 mg/L permissible limit in the absence of an alternate source సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: C. It shall not be detectable in any 100 mL sample సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: B. Potable water is suitable and safe for human drinking according to applicable quality requirements, whereas non-potable water does not meet or is not intended to meet those requirements సమాధానం: B.
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Question 20 ప్రశ్న 20Answer: A. Water at the source or entering treatment before the required treatment processes have been completed సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: A. Drinking-water source without conventional treatment but after disinfection సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: A. Drinking-water source after conventional treatment and disinfection సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: A. Conventional clarification and filtration followed by effective disinfection సమాధానం: A.
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Question 24 ప్రశ్న 24Answer: C. Nitrate సమాధానం: C.
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Question 25 ప్రశ్న 25Answer: B. Treatment should be selected from the actual physical, chemical and microbiological deficiencies of the raw water and the required finished-water quality సమాధానం: B.
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Question 26 ప్రశ్న 26Answer: D. I, II, III and IV సమాధానం: D.
