A thin uniform wire `AB` of length `1m`, an unknown resistance `X` and a resistance of `12 Omega` are connected by thick conducting strips, as shown in the figure. A battery and a galvanometer (with a sliding jockey connected to it) area also available. Connections are to be made to measure the unknown resistance `X` using the principle of Wheatstone bridge. Answer the following questions.

(a) Are there positive and negative terminals on the galvanometer ?
(b) Copy the figure in your answer book and show the battery and the galvanometer (with jockey) connected at apalphariate points.
( c) After apalphariate connections are made, it is found that no deflection takes place in the galvanometer when the sliding jockey touches the wire at a distance of `60 cm` from `A`. Obtain the value of the resistance `X`.

Explanation

(a) In galvanometer, only zeri deflection is required hence no need of positive and negative terminals.
(b)
( c) `AJ = 60 cm, BJ = 40 cm`
Wheatstone bridge is balanced
`(X)/(12) = (R_(BJ))/(R_(AJ)) = (40)/(60) = (2)/(3)`
`X = 8 Omega`.