Electrical Measurements and Instrumentation MCQs (Part-11)
What does calibration ensure in electrical measurement systems?
A Accuracy
B Sensitivity
C Voltage
D Power
Calibration ensures that an instrument provides accurate measurements by comparing it to a known reference. By adjusting the instrument to match the standard, calibration minimizes errors, ensuring precise and reliable results in measurements.
What type of error occurs due to instrument wear or drift over time?
A Systematic error
B Instrumental error
C Random error
D Gross error
Instrumental errors occur when an instrument’s accuracy degrades over time due to wear, aging, or mechanical failure. These errors can be minimized by regular calibration, maintenance, and using high quality equipment.
Which of the following reduces errors in measurements?
A Higher resistance
B Regular calibration
C Frequent measurements
D Large voltage
Regular calibration ensures that instruments are correctly adjusted to provide accurate readings. Calibration corrects any drift in the measurement system, reducing measurement errors and maintaining the reliability of the data.
What does dynamic characteristic of an instrument refer to?
A Response to changes
B Maximum voltage
C Accuracy over time
D Sensitivity
Dynamic characteristics refer to how quickly and accurately an instrument can respond to changes in the measured signal over time. It includes parameters like rise time, settling time, and frequency response, which are crucial for measuring rapidly changing signals.
What is a primary source of random errors in measurements?
A Instrument drift
B Human mistakes
C Environmental changes
D Statistical fluctuations
Random errors are caused by unpredictable fluctuations, such as minor variations in the environment, the instrument, or measurement conditions. They cannot be completely eliminated but can be minimized through repeated measurements and averaging.
What does an error analysis process help with?
A Identifying signal patterns
B Reducing data errors
C Enhancing instrument performance
D Identifying the type of error
Error analysis helps identify the source of errors in measurements, such as instrumental, environmental, or human errors. By understanding the errors, corrective actions can be taken to improve accuracy and reliability in measurements.
What is an example of a systematic error?
A Zero drift
B Temperature fluctuations
C Random noise
D Human mistake
Systematic errors occur consistently and lead to bias in measurements. Zero drift, where an instrument’s zero point shifts over time, is an example of a systematic error. These errors can be identified and corrected through calibration.
Which of the following is a dynamic characteristic of a measuring instrument?
A Resolution
B Linearity
C Sensitivity
D Speed of response
The speed of response is a dynamic characteristic that determines how quickly an instrument reacts to changes in the measured quantity. Faster response times are crucial when measuring rapidly changing signals or transient events.
How can human error in measurements be minimized?
A Using higher voltage
B Training and standard procedures
C Increasing signal strength
D Using smaller instruments
Human error can be minimized through proper training, following standardized measurement procedures, and using clear instructions. Consistency and careful handling are key to reducing mistakes during measurements.
What does precision in measurements refer to?
A Closeness to true value
B Consistency of results
C Response time
D Accuracy over time
Precision refers to how consistently an instrument produces the same result under identical conditions. A precise instrument provides similar readings when measuring the same quantity multiple times, even if it is not accurate.
What is the function of error correction in measurement systems?
A Increase signal strength
B Reduce environmental impact
C Adjust measurements to true values
D Stabilize power supply
Error correction in measurement systems adjusts the measured data to compensate for known errors or deviations, ensuring that the final readings closely match the true values. This process helps improve measurement accuracy.
Which of the following is true about precision instruments?
A They always provide accurate results
B They provide consistent results
C They measure large currents
D They work in extreme conditions
Precision instruments are designed to provide consistent measurements under the same conditions. While they may not always be accurate, they are reliable for producing reproducible results. Precision ensures that measurements are repeatable, even if biased.
What is the impact of noise on measurements?
A Reduces accuracy
B Increases precision
C Improves reliability
D Does not affect measurements
Noise, which is unwanted electrical interference, can distort the signal being measured and reduce the accuracy of the readings. Effective noise reduction techniques, such as shielding and filtering, are used to mitigate this impact.
What type of error can be minimized by using higher quality instruments?
A Systematic error
B Random error
C Environmental error
D Human error
High quality instruments are designed with higher precision and fewer defects, reducing systematic errors such as drift, calibration inaccuracies, or biases. Regular calibration of these instruments can further minimize systematic errors in measurements.
What does the linearity of a measurement system refer to?
A Its response time
B Its ability to measure small signals
C The accuracy of its output over a range of values
D Its resistance to noise
Linearity refers to how accurately a measurement system’s output represents the input value across a range of measurements. A linear system produces results directly proportional to the input value, ensuring consistent accuracy across all levels.