## Level Measurement Instrumentation Questions Answers

**Q1. What is the liquid level in the tank ?**

(Circle the correct option)

**75% of measured span**- 83% of measured span
- 50 % of measured span
- 25% of measured span

**Q2. In displacement type level measurement, which law is used ?**

- Charles law
- Ohms law
- Faradays law
**Archimedes principle**

**Q3. The weight of the displacer tube is 25 pounds. The buoyant force is 16 pounds when the displacer is submerged completely. What will be apparent weight of the displacer when submerged to 25% of water level?**

**21 pounds**- 17 pounds
- 25 pounds
- 16 pounds

**Q4. Under what circumstances would it be most appropriate to use dry leg system to measure the level in a closed vessel? (Circle the correct option)**

- Gas above the liquid condenses easily.
**Gas above the liquid cannot condense.**- Whenever a DP transmitter is used
- Only when a Gauge Pressure Transmitter

**Q5. In a wet leg system, the LP impulse line is completely filled with a liquid. This is**

- Just to create a negative pressure
- To compensate atmospheric pressure
**To avoid measurement error when the gas above the liquid condenses**

**Q6. In an HTG system, density cannot be calculated if the product volume is _________ the middle transmitter.**

- Above
**Below**- In level with

**Q7. Specific gravity of a material is the ratio of density of a material to the density of**

** _______Water_____**

**Q8. The boundary between the immiscible liquids is called**

**_______Interface_________.**

**Q9.In the interface level measurement using DP transmitter the assumptions are that at lower calibrated value the(4 mA point) , the tank is filled with ________ fluid ( heavier/lighter ) and at the upper calibrated value the tank is filled with ________________ fluid ( heavier/lighter).**

**Q10. In ultrasonic level measurement, if the round trip time is t, the distance **

** D= Velocity of _______Sound_____× t/2**

**Q11. A displacer level transmitter has a 30 inch tube and is used to measure the level of liquid with a specific gravity of 0.9. You need to calibrate the transmitter using sweet water. Calculate the depth of sweet water in which the displacer must be immersed to provide a maximum range output (20 mA) from the transmitter.**

**Ans: P = H * D**

** = 30 * 0.9**

** = 27 In**

**Q12. How do you do a zero check on a DP transmitter using 3 valve manifold ? **

Give Answer: **Or check in Comment**

Q13. In radar transmitter, The amount of reflected energy from the fluid surface is dependent on its dielectric constant. Is this statement True or False ?

Give Answer or **See in comment.**

**Q14. Can we use capacitor type level measurement if the process material is conducting ? **

**Yes**

**Q15. Calculate the calibrated points for zero and span in inches of H _{2}O.**

**4 mA ** = Y*SG – Z*SG

= 50*1.0 – 275*1.2

= 50-330

= -280 in H2O

**20 mA** = (X+Y)*SG – Z*SG

= 250*1.0 – 275*1.2

= 250 – 330

= -80 in H2O

**RANGE** -80 to -280 in H2O

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