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  • The potentiometer wire PQ is 100 cm long and its resistance is 2r. Where r is internal resistance of the battery. PC is equal to <img alt="" src="https://cdn.entrance360.com/media/uploads

The potentiometer wire PQ is 100 cm long and its resistance is 2r. Where r is internal resistance of the battery. PC is equal to

Option: 1

25 cm


Option: 2

75 cm


Option: 3

50 cm


Option: 4

40 cm


Answers (1)

best_answer

For galvanometer to show zero deflection, 

For galvanometer to show zero deflection,V_{P C}=\frac{E}{2}

\begin{aligned} & \Rightarrow \mathrm{i} \times \mathrm{R}_{\mathrm{PC}}=\frac{\mathrm{E}}{2} \quad \Rightarrow \frac{\mathrm{E}}{3 \mathrm{r}} \times \mathrm{R}_{\mathrm{PC}}=\frac{\mathrm{E}}{2} \quad \Rightarrow \mathrm{R}_{\mathrm{PC}}=\frac{3 \mathrm{r}}{2} \\ & \therefore \mathrm{PC}=\frac{3 \mathrm{r}}{\frac{2}{2 \mathrm{r}}} \times 100 \mathrm{~cm}=75 \mathrm{~cm} \end{aligned}

 

 

Posted by

Pankaj Sanodiya

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