| There are 32 cells each having \[emf 1\text{ }V\] and internal resistance \[1\text{ }\Omega \]. All the cells are connected together in a closed loop. When terminal voltage of cells are measured they are found to be either \[0.5V\] for \[1.5V\]. How many cells are having their polarities reversed with respect to the majority of cells? |
A) 6
B) 12
C) 8
D) 10
Correct Answer: C
Solution :
| if \[m\]cells are wrongly connected, then |
| \[{{\varepsilon }_{net}}=(32-2m)\varepsilon \] \[i=\frac{{{\varepsilon }_{net}}}{R}=\frac{(32-2m)\times 1}{32}=\left( \frac{32-2m}{32} \right)\] |
| Now \[V=\varepsilon -ir\] |
| \[0.5=1-\left( \frac{32-2m}{32} \right)\times 1\] On solving, \[m=8\]. |
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