In a meter bridge, the balancing length from the left end (standard resistance of $1 \,ohm$ is in the right gap) is found to be $20\, cm$. The value of the unknown resistance is ............... $\Omega$
  • A$0.8$
  • B$0.5$
  • C$0.4$
  • D$0.25$
AIPMT 1999, Easy
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