BEE FREE Bachelor of Electrical Engineering Measurement and Instrumentation Questions and Answers 2 — Questions and Answers
Question 1: What is the primary advantage of a digital multimeter over an analog multimeter?
- Higher input impedance and better accuracy (Correct answer)
- Lower cost and simpler construction
- Faster response time for transient signals
- Ability to measure only AC quantities
Correct answer: Higher input impedance and better accuracy
Digital multimeters offer higher input impedance (typically 10 MΩ or more) and superior accuracy compared to analog meters, reducing loading effects on the circuit under test.
Question 2: In a Wheatstone bridge circuit at balance condition, what is the current through the galvanometer?
- Maximum
- Equal to supply current
- Zero (Correct answer)
- Half of supply current
Correct answer: Zero
At balance, the potential difference across the galvanometer is zero, so no current flows through it.
Question 3: Which type of error is caused by incorrect reading of an instrument's scale by the observer?
- Systematic error
- Random error
- Parallax error (Correct answer)
- Instrumental error
Correct answer: Parallax error
Parallax error occurs when the observer's line of sight is not perpendicular to the instrument scale, causing incorrect readings.
Question 4: A LVDT (Linear Variable Differential Transformer) is used to measure which physical quantity?
- Temperature
- Pressure
- Linear displacement (Correct answer)
- Angular velocity
Correct answer: Linear displacement
An LVDT converts linear displacement of its core into a proportional electrical voltage output through electromagnetic induction.
Question 5: What does the resolution of a measuring instrument refer to?
- The maximum value it can measure
- The smallest change in input it can detect (Correct answer)
- The difference between measured and true value
- The range over which it maintains accuracy
Correct answer: The smallest change in input it can detect
Resolution is the smallest incremental change in the measured quantity that the instrument can detect or distinguish.
Question 6: Which instrument is most suitable for measuring very high resistances in the megaohm range?
- Kelvin double bridge
- Wheatstone bridge
- Megger (insulation resistance tester) (Correct answer)
- Ammeter-voltmeter method
Correct answer: Megger (insulation resistance tester)
A megger applies a high DC voltage and measures the resulting small current to determine insulation resistance in the megaohm to gigaohm range.
BEE FREE Bachelor of Electrical Engineering Measurement and Instrumentation Questions and Answers 2
What is the primary advantage of a digital multimeter over an analog multimeter?