Current Electricity - Result Question 57

60. The potential difference between the terminals of a cell in an open circuit is $2.2 V$. When a resistor of $5 \Omega$ is connected across the terminals of the cell, the potential difference between the terminals of the cell is found to be $1.8 V$. The internal resistance of the cell is

[2002]

(a) $\frac{7}{12} \Omega$

(b) $\frac{10}{9} \Omega$

(c) $\frac{9}{10} \Omega$

(d) $\frac{12}{7} \Omega$

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Answer:

Correct Answer: 60. (b)

Solution:

  1. (b) $E=V+i r$

$ \begin{aligned} & 2.2=1.8+\frac{1.8}{5} \times r \\ & \Rightarrow \quad r=\frac{10}{9} \Omega \end{aligned} $