• # question_answer A resistor ${{R}_{1}}$ dissipates the power P when connected to a certain generator. If the resistor ${{R}_{2}}$ is put in series with ${{R}_{1}}$, the power dissipated by ${{R}_{1}}$      [CPMT 1985; MNR 1998] A)            Decreases B)            Increases C)            Remains the same              D)            Any of the above depending upon the relative values of ${{R}_{1}}$ and ${{R}_{2}}$

Equivalent resistance in the second case $={{R}_{1}}+{{R}_{2}}=R$ Now, we know that $P\propto \frac{1}{R}$ Since in the second case the resistance $({{R}_{1}}+{{R}_{2}})$is higher than that in the first case (R1). Therefore power dissipation in the second case will be decreased.