Question 1:
The departure from the straight line relationship is
1. Linearity
2. Stiction
3. Drift
4. Non linearity
Answer: Non linearity
Explanation: Linearity
The ability to reproduce the input characteristics symmetrically is called linearity. It can be expressed by the straight line equation. The linearity is simply a measure of maximum deviation of any of the calibration points from the straight line (drawn by using the method of least square from the given calibration data). Fig. shows the actual calibration curve and a straight line drawn from the origin using method of least squares.
The linearity is simply a measure of maximum deviation of any of the calibration points from the straight line (drawn by using the method of least square from the given calibration data). Fig. shows the actual calibration curve and a straight line drawn from the origin using method of least squares. Any departure from straight line relationship is non-linearity. The non-linearity may be due to the following factors:
(i) Viscous flow or creep;
(ii) Non-linear elements in the measurement device;
(iii) Mechanical hysteresis;
(iv) The elastic after-effects in the mechanical system.
The two common types of non-linearity are:
1. Terminal linearity It is the deviation from a straight line through the end points.
2. Best fit linearity It is the deviation from the straight line which gives minimum errors, both plus and minus.
3. Fit a straight line into the following data.
a) y=3.52+2.26x
b) y=3.52
c) y=2.26x
d) y=4+3x
Answer: a
Explanation: Here, N=6
Calculations of Σx and Σx²
We know that, Σy=Na+b Σx [xy=a[x+b[x²
Substituting the values from the table into the equations -55 (6)a+b(15) - (1)
-177=(a)15+b(55) - (2)
Solving equations (1) and (2) simultaneously a=3.52 and b=2.26
Thus the equation of the line is given by y=a+bx Thus, the equation of the line is y=3.52+2.26x.