Search any question & find its solution
Question:
Answered & Verified by Expert
In the circuit shown below (on the left) the resistance and the emf source are both variable. The graph of seven readings of the voltmeter and the ammeter (V and I, respectively) for different setting of resistance and the emf, taken at equal intervals of time $\Delta t$, are shown (on the right) by the dots connected by the curve EFGH. Consider the interval resistance of the battery to be negligible and the voltmeter and ammeter to be ideal devices. Take $R_{0}=V_{0} I_{0}$
Then the plot of the resistance as a function of time corresponding to the curve EFGH is given by
Options:
Then the plot of the resistance as a function of time corresponding to the curve EFGH is given by
- A
- B
- C
- D
Solution:
1088 Upvotes
Verified Answer
The correct answer is:
From $\mathrm{E} \rightarrow \mathrm{F}$
Slope is constant
$V=\mid R$
Thus $R$ must be constant
$\mathrm{R}_{0}=\mathrm{V}_{0} / \mathrm{I}_{0}$
Frorm $\mathrm{F} \rightarrow \mathrm{G}$
$\mathrm{V}=$ constant
$\mathrm{I}$ is increase thus $\mathrm{R}$ must be decrease.
at $G, R=\frac{V_{0}}{2 I_{0}}=\frac{R_{0}}{2}$
From $\mathbf{G} \rightarrow \mathbf{H}$
$\mathrm{I}=$ constant
$\mathrm{V}=$ increase, thus $\mathrm{R}$ must be increase
$\mathrm{R}_{\mathrm{H}}=\frac{2 \mathrm{~V}_{0}}{2 \mathrm{l}_{0}}=\mathrm{R}_{0}$
Slope is constant
$V=\mid R$
Thus $R$ must be constant
$\mathrm{R}_{0}=\mathrm{V}_{0} / \mathrm{I}_{0}$
Frorm $\mathrm{F} \rightarrow \mathrm{G}$
$\mathrm{V}=$ constant
$\mathrm{I}$ is increase thus $\mathrm{R}$ must be decrease.
at $G, R=\frac{V_{0}}{2 I_{0}}=\frac{R_{0}}{2}$
From $\mathbf{G} \rightarrow \mathbf{H}$
$\mathrm{I}=$ constant
$\mathrm{V}=$ increase, thus $\mathrm{R}$ must be increase
$\mathrm{R}_{\mathrm{H}}=\frac{2 \mathrm{~V}_{0}}{2 \mathrm{l}_{0}}=\mathrm{R}_{0}$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.