NEET-XII-Physics
32: Electric Current in Conductors
- #13Two non-ideal batteries are connected in parallel. Consider the following statements:
(A) The equivalent emf is smaller than either of the two emfs.
(B) The equivalent internal resistance is smaller than either of the two internal resistances.
(a) A and B are correct.
(b) A is correct but B is wrong.
(c) B is correct but A is wrong.
(d) A and B are wrong.digAnsr: cAns : (c) B is correct but A is wrong.
The equivalent emf `` {\epsilon }_{0}`` , when two non-ideal batteries of emfs `` {\epsilon }_{1}`` and `` {\epsilon }_{2}`` and internal resistances r1 and r2 respectively are connected in parallel to each other, is given by:
`` {\epsilon }_{0}=\frac{{\epsilon }_{1}{r}_{1}+{\epsilon }_{2}{r}_{2}}{{r}_{1}+{r}_{2}}``
Thus, the equivalent emf is greater than either of the emfs. Thus, statement A is wrong.
For the parallel combination of the batteries of internal resistance r1 and r2, the equivalent internal resistance r is given as
`` r=\frac{{r}_{1}{r}_{2}}{{r}_{1}+{r}_{2}}``
Thus, the value of the resultant resistance is even smaller than either resistance.
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