Question

The internal resistance of two cells shown are 0.1 $\Omega$ and 0.3 $\Omega$. If $R=0.2\Omega$, the potential difference
across the cell

• A. B will be zero
• B. A will be zero
• C. $A\text{and}R\text{will be}2V$
• D. $A\text{will}be>2V\text{and}B\text{will be}<2V$

Answer 1

Answer: (A)

Applying Kirchoff's voltage law across the circuit

Current $I=-0.5I-0.3I+2V-0.1+3V-0$

$⟹0.6I=4$

$⟹I=\frac{40}{6}=\frac{20}{3}A$

For potential difference across $B$, moving across it we have,

$V_1-0.3\times \frac{20}{3}+2V=V_2$

$⟹V_1-2V+2V=V_2$

So, potential difference across $B$ is $0$