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Question
100 cells each of emf 5 V and internal resistance 1 Ω are to be arranged so as to produce maximum current in a 25 Ω resistance. Each row contains equal number of cells. The number of rows should be ______.
Options
2
4
5
100
Solution
100 cells each of emf 5 V and internal resistance 1 Ω are to be arranged so as to produce maximum current in a 25 Ω resistance. Each row contains equal number of cells. The number of rows should be 2.
Explanation:
let, m = Number of rows
n = Number of cells in a row
∴ m × n = 100 ....(i)
Resistance in series = nr
Resistance in parallel = `("nr")/"m"`
For maximum current, R = `("nr")/"m"`
25 = `"n"/"m"` ........(r = 1 Ω) ....(ii)
From equations (i) and (ii),
m = 2
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