Question

In the given circuit, it is observed that the current I is independent of the value of the resistance $R_6$. Then, the resistance values must satisfy

• A. $R_1R_2R_5=R_3R_4R_6$
• B. $\frac{1}{R_5}+\frac{1}{R_6}=\frac{1}{R_1+R_2}+\frac{1}{R_3+R_4}$
• C. $R_1R_4=R_2R_3$
• D. $R_1R_3=R_2R_4$

Answer 1

Answer: (C)

$R_1R_4=R_2R_3$

Answer 2

Current I can be independent of $R_6$ only when $R_1,R_2,R_3,R_4$ and $R_6$ form a balanced Wheatstone's bridge.
Therefore, $\frac{R_1}{R_2}=\frac{R_3}{R_4}$
or $R_1R_4=R_2R_3$