Question 214: Current Electricity

Question

Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is :

Accepted Answer

$$I = {{2\varepsilon } \over {R + {r_1} + {r_2}}}$$
As per the question,
$${{2\varepsilon } \over {R + {r_1} + {r_2}}} 	imes {r_2} - \varepsilon  = 0$$
$$ \Rightarrow R = {r_2} - {r_1}$$

Answer

r2 $$-$$ r1

Answer

r1 $$-$$ r2

Answer

r1

Answer

r2

Current Electricity

Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is :

Choose the correct answer: