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Two sources of current of equal emf are connected in series and having different internal resistance `r_1` and `r_2(r_2gtr_1)`. Find the external resistance `R` at which the potential difference across the terminals of one of the sources becomes equal to zero. |
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Answer» `V=E-ir` `E` and `i` for both the sources are equal. Therefore, potential difference (`V`) will be zero for a source having greater internal resistance i.e. `r_2` `:. 0=E-ir_2` or `E=ir_2=((2E)/(R+r_1_r_2)).r_2` `:. 2r_2=R+r_1+r_2` or `R=r_2-r_1` |
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