Current Electricity Ques 18
18. Five resistances have been connected as shown in the figure. The effective resistance between $A$ and $B$ is
[2000]
(a) $\frac{14}{3} \Omega$
(b) $\frac{20}{3} \Omega$
(c) $14 \Omega$
(d) $21 \Omega$
Show Answer
Answer:
Correct Answer: 18.(a)
Solution:
- (a) It is a balanced wheatstone bridge $(\because \frac{3}{4}=\frac{6}{8})$, so the $7 \Omega$ resistance is ineffective. Equivalent resistance of $3 \Omega$ and $4 \Omega=3+4$ $=7 \Omega$ (series)
Equivalent resistance of $6 \Omega$ and $8 \Omega=6+8$
$=14 \Omega$ (series)
Equivalent resistance of $7 \Omega$ and $14 \Omega$ (parallel)
$=\frac{7 \times 14}{7+14}=\frac{14}{3} \Omega$
BETA
