Errors

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:

                  (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