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Wheatstone Bridge and Its Applications |
Wheatstone bridge is an arrangement of four resistances P, Q, R and S connected as shown in the figure. Their values are so adjusted that the galvanometer G shows no deflection. The bridge is then said to be balanced when this condition is achieved. In the setup shown here, the points B and D are at the same potential and it can be shown that\[\frac{P}{Q}=\frac{R}{S}\]. |
This is called the balancing condition. If any three resistances are known the fourth can be found. |
The practical form of wheatstone bridge is slide wire bridge or meter bridge. Using this the unknown resistance can be determined as \[S=\left( \frac{100-l}{l} \right)\times R\] where l is the balancing length of the Meter bridge. |
A) \[9\,\Omega \]
B) \[7\,\Omega \]
C) \[10\,\Omega \]
D) \[5\,\Omega \]
Correct Answer: B
Solution :
\[\left( S+x \right)=\frac{Q}{P}R\] \[x=\frac{Q}{P}R-S=\frac{6}{5}\times 10-5=7\Omega \]You need to login to perform this action.
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