Current Electricity 2 Question 15
15. 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
(2001, 2M)
(a) $R _1 R _2 R _5=R _3 R _4 R _6$
(b) $\frac{1}{R _5}+\frac{1}{R _6}=\frac{1}{R _1+R _2}+\frac{1}{R _3+R _4}$
(c) $R _1 R _4=R _2 R _3$
(d) $R _1 R _3=R _2 R _4$
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Solution:
- 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, $\quad \frac{R _1}{R _2}=\frac{R _3}{R _4}$ or $R _1 R _4=R _2 R _3$
