Current Electricity Ques 70
- 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
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Answer:
Correct Answer: 70.(a)
Solution:
Formula:
- $P=i^{2} R$
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} $
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