cells `A` and `B` and a galvanometer `G` are connected to a side wire `OS` by two sliding contacts
Channel: Doubtnut
Date: 2020-08-02

cells `A` and `B` and a galvanometer `G` are connected to a side wire `OS` by two sliding contacts `C` and `D` as shows in Fig. `6.17`. The slide wire is `100 cm` long and has a resistance of `12 Omega`. With `OD = 75 cm`, the galvanometer gives no deflections when `OC` is `50 cm`. If `D` is moved to touch the end of wire `S`, the value of `OC` for which the galvanometer shows no deflection is `62.5 cm`. The emf of cell `B` is `1.0 V`. Calculate  (i) the potential difference across `O` and `D` when `D` is at `75 cm` mark from `O`  (ii) the potential difference across `OS` when `D` touches `S`  (iii) internal resistance of cell `A`  (iv) the emf of cell `A`