Question
Consider a simple circuit shown in Fig. stands for a variable resistance $R\ '. R\ '$ can vary from $R_0$ to infinity. $r$ is internal resistance of the battery $(r < < R < < R_0).$
✓
Answer
a. Potential drop across $AB$ is nearly constant as $R\ '$ is varied.
d.$\ \text{I}\geq\frac{\text{V}}{\text{r}+\text{R}}$ always.
Solution:
Key concept: Parallel grouping
Same potential difference appeared across each resistance but current distributes in the reverse ration of their resistance, i.e. $\text{i}\propto\frac{\text{l}}{\text{R}}$
In this problem, the potential drop is taking place across $AB$ and $r$.
Since the equivalent resistance of parallel combination of $R$ and $R\ '$ is always less than $R$,
therefore current will be greater than or equal to $\text{I}\geq\frac{\text{V}}{\text{r}+\text{R}}$ always.
Important poin: in parallel combination of resistances, the equivalent resistance is smaller than smallest resistance present in combination.
d.$\ \text{I}\geq\frac{\text{V}}{\text{r}+\text{R}}$ always.
Solution:
Key concept: Parallel grouping
Same potential difference appeared across each resistance but current distributes in the reverse ration of their resistance, i.e. $\text{i}\propto\frac{\text{l}}{\text{R}}$
In this problem, the potential drop is taking place across $AB$ and $r$.
Since the equivalent resistance of parallel combination of $R$ and $R\ '$ is always less than $R$,
therefore current will be greater than or equal to $\text{I}\geq\frac{\text{V}}{\text{r}+\text{R}}$ always.
Important poin: in parallel combination of resistances, the equivalent resistance is smaller than smallest resistance present in combination.
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