Question: Q. 2. An alternating current generator has an internal resistance $R_{g}$ and an internal reactance $X_{g}$. It is used to supply power to a passive load consisting of a resistance $R_{g}$ and a reactance $X_{L}$. For maximum power to be delivered from the generator to the load, the value of $X_{L}$ is equal to (a) zero. (b) $X_{g}$ (c) $-X_{g}$. (d) $R_{g}$.
[NCERT Exemplar]
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Solution:
Ans. Correct option : (c)
Explanation : As internal resistance of generator is already equal to external resistance $R_{g}$. So to deliver maximum power, i.e., to make reactance equal to zero, the reactance in external circuit will be $-X_{g}$. In order to deliver maximum power, the generator to the load, the total reactance must be equal to zero, i.e.,
$$ X_{L}+X_{g}=0 \text { or } X_{L}=-X_{g} $$
