Question
Draw a circuit diagram using a metre bridge and write the necessary mathematical relation used to determine the value of an unknown resistance. Why cannot such an arrangement be used for measuring very low resistances?
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Answer
$\text{R} = \frac{\ell_{1}}{\big(100 - \ell_{1}\big)}$
End correction can be comparable with the low resistance used or unknown contact resistance (strips of connecting wires) becomes comparable with low resistance to be measured.
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