Systematic errors in experimental observations usually come from the measuring instruments. They may occur because of poor calibration of the instrument or its data handling system, or because the instrument is wrongly used by the experimenter.
Systematic errors can be minimized by improving experimental techniques, selecting better instruments, and removing personal bias as far as possible.
12. The instruments that determine the electrical quantity to be measured directly in terms of deflection are called:
Absolute instruments
Integrating instruments
Secondary instruments
Recording instruments
Answer.3. Secondary instruments
Explanation:
Secondary instruments are so constructed that the quantity being measured can only be measured by observing the output indicated by the instrument i.e. deflection of the instrument
These instruments are calibrated by comparison with an absolute instrument or any other secondary instrument which has already been calibrated against an absolute instrument
A voltmeter, a glass thermometer, and a pressure gauge are typical examples of secondary instruments
13. ______ are caused by the inertial properties of measuring instruments or equipment.
Dynamic Error
Random Error
Systematic Error
Gross Error
Answer.1. Dynamic Error
Explanation:
Dynamic errors are caused by the inertial properties of measuring instruments or equipment. Consider that a varying quantity is recorded with the help of a recording device. Then the difference between the obtained function and the actual process of change of the recorded quantity in time is called the dynamic error of the given dynamic instrument. It is clear that these errors are caused by the time variation in the measured quantity.
14. If a zero-centered voltmeter has a scale from – 5V to +5V, then the span of it is _____.
0 V
10 V
5 V
–5 V
Answer.2. 10 V
Explanation:
The voltmeter scale is -5 V to 5 V
If voltmeter scale is -V1 to V2, then the span is given by (V2 + V1)
Now, span = 5 + 5 = 10 V
15. ______ error arises in the measurement due to the effect of the external conditions on the measurement.
Observational Error
Instrumentational Error
Gross Error
Environmental Error
Answer.4. Environmental Error
Explanation:
The environmental error arises due to external conditions, which include temperature, pressure, humidity, external magnetic field, etc. We can minimize the environmental errors by maintaining the temperature and humidity of the laboratory constant through some arrangements, and ensuring that there is no external magnetic or electrostatic field around the instrument.
16. Repeatability and reproducibility are related to
Accuracy of the instrument
The precision of the instrument
Both accuracy of the instrument & precision of the instrument
None of these
Answer.2. The precision of the instrument
Explanation:
Repeatability measures the variation in measurements taken by a single instrument or person under the same conditions, while reproducibility measures the degree of closeness with which a given value may be repeatedly measured. It may be specified in terms of units for a given period of time.
Repeatability and reproducibility are related to the precision of the instrument.
17. The type of Systematic Errors are
Environmental Error
Observational Error
Instrumental Error
All of the above
Answer.4. All of the above
Explanation:
Systematic errors are Divided into three parts
Environmental Errors
Observational Errors
Instrumental Errors
Environmental Errors: This type of error arises in the measurement due to the effect of external conditions on the measurement. The external condition includes temperature, pressure, and humidity and can also include an external magnetic field.
Observational Errors: Observational error (or measurement error) is the difference between a measured value of a quantity and its true value. These are the errors that arise due to an individual’s bias, lack of proper setting of the apparatus, or an individual’s carelessness in taking observations. The measurement errors also include wrong readings due to Parallax errors.
Instrumental Errors: This error may arise due to imperfection or faulty adjustment of the instrument with which measurement is being taken.
18. The change in resistance of an electrical strain gauge with a gauge factor of 2.0 and resistance of 50 Ω when subjected to a strain of 0.001 is:
0.1 Ω
0.01 Ω
0.001 Ω
0.0001 Ω
Answer.1. 0.1 Ω
Explanation:
Given-
GF = 2, R = 50 Ω, ε = 0.001
Now change in resistance of an electrical strain gauge can be calculated as
ΔR = 2 × 50 × 0.001
ΔR = 0.1 Ω
19. _______ is an error in which an instrument gives a reading when the true reading at that time is zero.
Maximum Error
Negative Error
Zero Error
Numerical Error
Answer.3. Zero Error
Explanation:
Zero Error is a type of error in which an instrument gives a reading when the true reading at that time is zero. For example needle of the ammeter fails to return to zero when no current flows through it.
20. Null type recorders are __________ recorders.
Potentiometric
Bridge
LVDT
Any of these
Answer.4. Any of these
Explanation:
Null type instrument: An instrument in which zero or null indication determines the magnitude of the measured quantity, such type of instrument is called a null type instrument.
It uses a null detector which indicates the null condition when the measured quantity and the opposite quantity are the same.