Three identical resistors, each of resistance $R$, are connected in **parallel**. The equivalent resistance is:
A$\dfrac{R}{3}$
B$R$
C$3R$
D$R^3$
Answer & Solution
Correct answer: A. $\dfrac{R}{3}$
For $n$ identical resistors in parallel: $\dfrac{1}{R_{eq}} = \dfrac{n}{R} \Rightarrow R_{eq} = \dfrac{R}{n}$. With $n = 3$, $R_{eq} = \dfrac{R}{3}$.
In parallel the equivalent is always *less than the smallest* component — and option C ($3R$) is the series result, the most common trap.
Related questions
For a battery of emf ε and internal resistance r driving current I through external resistA galvanometer of resistance G is converted into a voltmeter reading full-scale voltage V A galvanometer of resistance G shows full-scale deflection at current I_g. To convert it iThe relation between current density j, drift velocity v_d, number density n and charge e A wire has a resistance R. It is stretched uniformly so that its length becomes 2L. The neKirchhoff current law at a junction is a statement ofTwo cells of emf ε and internal resistance r each are connected in parallel. The equivalenA potentiometer of length L is used to compare emfs. If the balance lengths for cells of e