A) 50 cm
B) 80 cm
C) 40 cm
D) 70 cm
Correct Answer: A
Solution :
In balancing condition, \[\frac{{{R}_{1}}}{{{R}_{2}}}=\frac{{{l}_{1}}}{{{l}_{2}}}=\frac{{{l}_{1}}}{100-{{l}_{1}}}\] Þ \[\frac{X}{Y}=\frac{20}{80}=\frac{1}{4}\] .....(i) and \[\frac{4X}{Y}=\frac{l}{100-l}\] .....(ii) Þ\[\frac{4}{4}=\frac{l}{100-l}\] Þ \[l=50\,cm\]You need to login to perform this action.
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