250+ TOP MCQs on Instrumentation used in a Water Treatment Plant and Answers

Waste Water Engineering Multiple Choice Questions on “Instrumentation used in a Water Treatment Plant”.

1. pH sensor must remain clean for an accurate reading.
a) True
b) False
Answer: a
Clarification: For a pH sensor to maintain an accurate reading, the sensor must remain clean. Specifically, the glass measuring electrode cannot become coated and the reference electrode assembly must not become coated, plugged or otherwise contaminated by the process solution.

2. _______ is suited for open channel monitoring applications.
a) pH sensor
b) Ultrasonic technology
c) Infrared technology
d) Monitoring meters
Answer: b
Clarification: Ultrasonic level technology has been uncontested as the standard for level and OCM applications in the water industry.

3. How many categories of process variables are present?
a) 2
b) 3
c) 4
d) 5
Answer: b
Clarification: There are three categories of process variables. Instrumentation and automatic control allow continuous monitoring of process variables, rapid transfer of data to the operator or manager.

4. Which of the following are a mechanical means of signal transmission?
a) Detector
b) Tone
c) Amplifier
d) Indicator
Answer: d
Clarification: The mechanical means of signal transmission include movement of a pen, indicator, float or cable. Pneumatic means include a detector or an amplifier. Electronic means include voltage, current, pulse duration, etc.

5. Which of the following are a pneumatic means of signal transmission?
a) Cable
b) Indicator
c) Amplifier
d) Current
Answer: c
Clarification: Pneumatic means include a detector or an amplifier. The mechanical means of signal transmission include movement of a pen, indicator, float or cable. Electronic means include voltage, current, pulse duration, etc.

6. Tone is an electronic means of the signal transmission device.
a) True
b) False
Answer: a
Clarification: Electronic means include voltage, current, pulse duration, etc. The mechanical means of signal transmission include movement of a pen, indicator, float or cable. Pneumatic means include a detector or an amplifier.

7. Which of the following is not a read out device?
a) Float
b) Computer screens
c) Indicators
d) Recorders
Answer: a
Clarification: The most common type of read out devices is indicators, recorders and totalizer on panels of computer screens. The display is placed locally, close to the equipment site or at a central operating room for the whole family.

8. How many types of time control systems are present?
a) 2
b) 3
c) 4
d) 5
Answer: b
Clarification: There are three types are time control systems present in wastewater engineering. They are digital, analog and automatic control systems.

9. What is modern data acquisition systems called?
a) CADA
b) SCADA
c) CAED
d) CAD
Answer: b
Clarification: Data acquisition systems effectively accumulate, format, record and display data transmitted by sensors. Modern data acquisition systems are called as Supervisory Control and Data Acquisition (SCADA) systems.

10. What is the price of water process analyser?
a) Rs. 380
b) Rs. 485
c) Rs. 525
d) Rs. 695
Answer: b
Clarification: Water process analyser consists of single and dual Channels with a one step, push button calibration which displays DO and temperature for each channel.

11. What is the maximum percentage of saturation for dissolved oxygen analyser?
a) 98.9%
b) 99.2%
c) 99.8%
d) 99.9%
Answer: d
Clarification: Percent of saturation for dissolved oxygen analyser is 0 – 99.9%. Two methods of calibration are: standard with automatic temperature, altitude and salinity compensation and the other is Isolated with 4 – 20 mA, digital serial output.

12. What is the maximum concentration measured by a 72 series water process analyser?
a) 1500 mg/l
b) 3000 mg/l
c) 3500 mg/l
d) 4000 mg/l
Answer: a
Clarification: • 72 Series: 10 – 1500 mg/l
• 73 Series: 300 – 30,000 mg/l
• 74 Series: 800 – 80,000 mg/l.