In a potentiometer experiment, when a cell in the secondary circuit is shunted by a resistance ' $R$ ',…

In a potentiometer experiment, when a cell in the secondary circuit is shunted by a resistance ' $R$ ', balancing length is ' $L_1$ '. On doubling the shunt resistance, balancing length increases to ' $L_2$ '. Internal resistance of the cell is
  1. $\frac{2 \mathrm{R}\left(\mathrm{L}_2-\mathrm{L}_1\right)}{\mathrm{L}_1-2 \mathrm{~L}_2}$
  2. $\frac{2 \mathrm{R}\left(\mathrm{L}_2-\mathrm{L}_1\right)}{\left(2 \mathrm{~L}_1-\mathrm{L}_2\right)}$
  3. $\frac{\mathrm{R}\left(\mathrm{L}_2-\mathrm{L}_1\right)}{\mathrm{L}_1-2 \mathrm{~L}_2}$
  4. $\frac{\mathrm{R}\left(\mathrm{L}_2-\mathrm{L}_1\right)}{\left(2 \mathrm{~L}_1-\mathrm{L}_2\right)}$

Solution

No solution. Refer to answer key.

Asked in: AP EAMCET 2017 (24 Apr Shift 1)

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