Current Electricity 3 Question 9
8. The three resistances of equal value are arranged in the different combinations shown below. Arrange them in increasing order of power dissipation
$(2003,2 M)$
(a) III $<$ II $<$ IV $<$ I
(b) II $<$ III $<$ IV $<$ I
(c) I $<$ IV $<$ III $<$ II
(d) I $<$ III $<$ II $<$ IV
Show Answer
Solution:
- $P=i^{2} R$
Current is same, so $P \propto R$.
In the first case it is $3 r$, in second case it is $\frac{2}{3} r$, in third case it is $\frac{r}{3}$ and in fourth case the net resistance is $\frac{3 r}{2}$.
$$ \begin{array}{rlrl} & & R _{\text {III }}<R _{\text {II }}<R _{\text {IV }}<R _{II} \\ \therefore & P _{\text {III }}<P _{\text {II }}<P _{\text {IV }}<P _I \end{array} $$
