Question

In the following circuit the potential difference between the points B and C is balanced against 40 cm length of potentiometer wire. In order to balance the potential difference between the points C and D, where should jockey be pressed

• A. 32 cm
• B. 16 cm
• C. 8 cm
• D. 4 cm

Answer 1

The correct option is A 32 cm

$\frac{1}{R}=\frac{1}{10}+\frac{1}{10}=\frac{2}{10}=\frac{1}{5}$ or $R_1=5\Omega$
$R_2=4\Omega ,I_1=40cm,I_2=?$
$l_2=l_1\frac{R_2}{R_1}$ or $l_2=\frac{40\times 4}{5}=32cm$