Question

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

• A. B will be zero
• B. A will be zero
• C. A and B will be 2V
• D. A will be and B will be

Answer 1

Answer: (A)

B will be zero

Answer 2

Applying Kirchhoff law

$( 2 + 2 ) = ( 0.1 + 0.3 + 0.2 ) i$ ⇒ $i = \frac { 20 } { 3 } A$

Hence potential difference across A

$= 2 - 0.1 \times \frac { 20 } { 3 } = \frac { 4 } { 3 } V$ (less than 2V)

Potential difference across

$B = 2 - 0.3 \times \frac { 20 } { 3 } = 0$