Question

The equivalent resistance of a group of resistances is $R$. If another resistance is connected in parallel to the group, its new equivalent becomes $R_1$ & if it is connected in series to the group, its new equivalent becomes $R_2$. We have

• A. $R_1>R$
• B. $R_1=R$
• C. $R_2>R$
• D. $R_2<R$

Answer 1

The correct option is C $R_2>R$

Let another resistance connected to resistance $R$ be $R^{\prime }$.

In parallel combination, equivalent resistance $R_1$ is less than the minimum value of any resistance connected in circuit,
$i.e.R_1<R\text{or}{R}^{\prime }$.

In series, equivalent resistance $R_2$ is greater than the maximum value of any resistance given in the circuit,
$i.e.R_2>R\text{or}{R}^{\prime }.$

Hence, option $\left(c\right)$ is correct.