Question

For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and the internal resistance of the cell are E and r, respectively. Then

• A. $E=2V,r=0.5\Omega$
• B. $E=2V,r=0.4\Omega$
• C. $E>2V,r=0.5\Omega$
• D. $E>2V,r=0.4\Omega$

Answer 1

The correct option is B

$E=2V,r=0.4\Omega$

V = E - ir. When I = 0, the potential reading is 2V. Hence e.m.f = 2V. When V = 0, I = 5A. This gives $r=0.4\Omega$