1.

100 cells each of emf 5V and internal resistance `1 Omega` are to be arranged to produce maximum current in a `25 Omega` resistance. Each row contains equal number of cells. Find the number of rows.A. 2B. 3C. 50D. 40

Answer» Correct Answer - A
Let n be the number of cells in a row and m be the number of rows.
Now, maximum current is obtained for `r=R`. In mixed combination total resistance of the circuit is given by,
`R=(nr)/(m) :.25(n)/(m) r :. (n)/(m)=25`
`:.n=25m` ....(i)
In mixed combination, we have,
`nm=100` ...(ii)
From equation (i) and (ii) we have,
`mxx25m=100`
`25m^(2)=100`
`m^(2)=4:.m=2 ` and `n=50`


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