Question

By a cell a current of 0.9 A flows through 2 ohm resistor and 0.3 A through 7 ohm resistor. The internal resistance of the cell is

• A. $0.5 \Omega$
• B. $1.0 \Omega$
• C. $1.2 \Omega$
• D. $2.0 \Omega$

Answer 1

Answer: (A)

$0.5 \Omega$

Answer 2

0.9 (2 + r) = 0.3 (7 + r) ⇒ 6 + 3r = 7 + r

⇒ r = 0.5 Ω