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Question:
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In a meter bridge, the point $\mathrm{D}$ is a neutral point (figure).
Options:
- A
The meter bridge can have no other neutral. A point for this set of resistances
- B
When the jockey contacts a point on meter wire left of D, current flows to B from the wire
- C
When the jockey contacts a point on the meter wire to the right of D, current flows from $B$ to the wire through galvanometer
- D
When $R$ is increased, the neutral point shifts to left
Solution:
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Verified Answer
The correct answers are:
The meter bridge can have no other neutral. A point for this set of resistances
,
When the jockey contacts a point on the meter wire to the right of D, current flows from $B$ to the wire through galvanometer
The meter bridge can have no other neutral. A point for this set of resistances
,
When the jockey contacts a point on the meter wire to the right of D, current flows from $B$ to the wire through galvanometer
As we know that, the principal of meter bridge
$$
\frac{\mathrm{R}}{\mathrm{S}}=\frac{\mathrm{L}}{(100-\mathrm{L})}
$$
When Jockey is at $\mathrm{D}$, the current does not flow through galvanometer. So the potential at B and D are equal. The point $\mathrm{D}$ is unique to get null point.
At neutral point, potential at B and neutral point are same. When jockey is placed at to the right of $\mathrm{D}$, the potential drop across $\mathrm{AD}$ is more than potential drop across $\mathrm{AB}$, which brings the potential of point $D$ less than that of $B$, hence current flows from B to D.
$$
\frac{\mathrm{R}}{\mathrm{S}}=\frac{\mathrm{L}}{(100-\mathrm{L})}
$$
When Jockey is at $\mathrm{D}$, the current does not flow through galvanometer. So the potential at B and D are equal. The point $\mathrm{D}$ is unique to get null point.
At neutral point, potential at B and neutral point are same. When jockey is placed at to the right of $\mathrm{D}$, the potential drop across $\mathrm{AD}$ is more than potential drop across $\mathrm{AB}$, which brings the potential of point $D$ less than that of $B$, hence current flows from B to D.
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