A potentiometer wire of length $$100$$ cm has a resistance $$5$$ ohm . It is connected in series with a resistance and a cell of emf $$2$$ V and of negligible internal resistance. A source of emf $$5$$ mV balanced by $$10$$ cm length of potentiometer wire. The value of external resistance $$is_____$$

Question

A potentiometer wire of length $$100$$ cm      has a resistance $$5$$ ohm     . It is connected in series with a resistance and a cell of  emf $$2$$ V      and of negligible  internal resistance. A source of emf $$5$$ mV      balanced by $$10$$ cm      length of  potentiometer wire. The value of external resistance $$is_____$$

Infinity Learn · Accepted Answer

Potentiometer wire of length $$L=100$$ cm       Resistance $$R=5$$ Ω     Cell of emf $$E=2$$ V     Source of emf $$E1=5$$ mV     Balancing length $$l=10$$ cm     $$E1=(ER+RS)$$ RLl     $$5$$×$$10$$−$$3=(25+RS)$$ $$5100$$×$$10$$     $$5$$×$$10$$−$$3=2$$×$$5$$×$$10(5+RS)100$$     ∴$$RS=$$ $$195$$ Ω

A potentiometer wire of length $100 c m$ has a resistance $5 o h m$ . It is connected in series with a resistance and a cell of emf $2 V$ and of negligible internal resistance. A source of emf $5 m V$ balanced by $10 c m$ length of potentiometer wire. The value of external resistance is_____

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A potentiometer wire of length 100 cm has a resistance 5 ohm . It is connected in series with a resistance and a cell of emf 2 V and of negligible internal resistance. A source of emf 5 mV balanced by 10 cm length of potentiometer wire. The value of external resistance is_____

Remember concepts with our Masterclasses.

Ready to Test Your Skills?

free study material

A potentiometer wire of length $100 c m$ has a resistance $5 o h m$ . It is connected in series with a resistance and a cell of emf $2 V$ and of negligible internal resistance. A source of emf $5 m V$ balanced by $10 c m$ length of potentiometer wire. The value of external resistance is_____