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>> Errors and Error Analysis
The major systematic errors in this experiment are due to the heating effect, end corrections introduced due to shift of the zero of the scale at A and B, and stray resistances in P and Q, and errors due to non-uniformly of the meter bridge wire.
End corrections can be estimated by including known resistances P1and Q1 in the two ends and finding the null point:
(where a and b are the end corrections).
When the resistance Q1 is placed in the left gap and P1 in the right gap,
which give two linear equation for finding a and b.
In order that aand b be measured accurately, P1 and Q1 should be as different from each other as possible.
For the actual balance point,
Errors due to non-uniformity of the meter bridge wire can be minimized by interchanging the resistances in the gaps P and Q.
Where d and d are the order of the least count of the scale.
The error is, therefore, minimum if = , i.e. when the balance point is in the middle of the bridge.
The error in r is