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# In a metre bridge , the balance point is found to be at $39.5\;cm$ from the end A, when the resistor Y is of $12.5 \;ohm$. Determine the resistance of x. Why are the connections between resistors in a metre bridge made of thick copper ships ? What happens if the galvanometer and cell are interchanged at the balanced point of the bridge ? would the galvanometer show any current?

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A)
Solution :
$l= 39.5 \;cm$
$y= 12.5 \;\Omega$
We know that $\large\frac{x}{y}=\frac{l_1}{l_2}$
(ie) $\large\frac{x}{y}=\frac{39.5}{100-39.5}$
$x= \large\frac{39.5}{60.5 }$$\times 12.5$
$\quad= 8 \Omega$
b) Thick copper slips provide very low resistance
Hence the reading is not affected due to copper strips.
c) If the galvanometer and cell are interchange it will not affect the balance point.
d) The galvanometer will not show any reading