Two resistances are connected in two gaps of a metre bridge. The balance point is $$20$$ cm from the zero end. A resistance of $$15$$ ohms is connected in series with the smaller of the two. The null point shifts to $$40$$ cm. The value of the smaller resistance in ohms is

Question

Infinity Learn · Accepted Answer

Let S be larger and R be smaller resistances connected in two gaps of meter bridge.∴     S $$=$$ $$100$$−ll $$R=$$   $$100$$−$$2020$$ $$R=4R$$            ….(i)When$$ $$15$$  Ω resistance is added to resistance R, $$thenS=$$   $$100$$−$$4040$$ $$R+15=64R+15$$                  ….$$(ii)From$$ equations $$(i) and (ii),  R $$=9$$ Ω

Two resistances are connected in two gaps of a metre bridge. The balance point is 20 cm from the zero end. A resistance of 15 ohms is connected in series with the smaller of the two. The null point shifts to 40 cm. The value of the smaller resistance in ohms is

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