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.

Error Analysis

End corrections can be estimated by including known resistances P1and Q1 in the two ends and finding the null point:

1447_image045.gif  (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 1059_image049.gif = 610_image050.gif, i.e. when the balance point is in the middle of the bridge.

The error in r is 680_image051.gif

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