A cell gives a current of 0.15A through a resistance of 8\(\Omega\) and 0.3A. When the resistance is changed to 3\(\Omega\) the internal resistance of the cell is
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Correct Answer: Option D
Explanation:
The E.M.F of a circuit is given byÂ
\(E=I(R+r)\)
Hence, E = 0.15(8+r)Â = 0.3(3+r)
1.2 + 0.15r = 0.9 + 0.3r
1.2 - 0.9 = 0.3r - 0.15r
0.3 = 0.15r
r = \(\frac{0.3}{0.15}\)
r = 2\(\Omega\)
The E.M.F of a circuit is given byÂ
\(E=I(R+r)\)
Hence, E = 0.15(8+r)Â = 0.3(3+r)
1.2 + 0.15r = 0.9 + 0.3r
1.2 - 0.9 = 0.3r - 0.15r
0.3 = 0.15r
r = \(\frac{0.3}{0.15}\)
r = 2\(\Omega\)