3.15 M ETER B RIDGE

. M ETER B RIDGE The meter bridge is shown in Fig. . . It consists of a wire of length 1m and of uniform cross sectional area stretched taut and clamped between two thick metallic strips bent at right angles, as shown. The metallic strip has two gaps across which resistors can be connected. The end points where the wire is clamped are connected to a cell through a key. One end of a galvanometer is connected to the metallic strip midway between the two gaps. The other end of the galvanometer is connected to a ‘jockey’. The jockey is essentially a metallic rod whose one end has a knife-edge which can slide over the wire to make electrical connection. R is an unknown resistance whose value we want to determine. It is connected across one of the gaps. Across the other gap, we connect a FIGURE . A meter bridge. Wire AC is m long. R is a resistance to be measured and S is a standard resistance.