A cell of e.m.f. 1.5V is connected in series with a resistor of resistance 3.0\(\Omega\). A voltmeter connected across the cell registers 0.9V. Calculate the internal resistance of the cell
A
2.0\(\Omega\).
B
3.0\(\Omega\).
C
5.0\(\Omega\).
D
6.0\(\Omega\).
Verified Correct Answer: A.
Physical Principles & Numerical Solution
\(\frac{V}{R} = \frac{E}{R + r}\)
\(\frac{0.9}{3} = \frac{1.5}{3 + r}\)
r = 2\(\Omega\).
Source: Myschool Past Questions Archive (Record #35208)