Three equal resistances each of value R. are joined as shown in the figure. The equivalent resistance between M and N is
A) R
B) 2R
C) R/2
D) R/3
Correct Answer:
D
Solution :
All 3 resistances are in parallel. \[\therefore \] By \[\frac{1}{R}=\frac{1}{{{R}_{1}}}+\frac{1}{{{R}_{2}}}+\frac{1}{{{R}_{3}}}\] or \[\frac{1}{{{R}_{eq}}}=\frac{1}{R}+\frac{1}{R}+\frac{1}{R}\] \[\Rightarrow \] \[{{R}_{eq}}=\frac{R}{3}\]