question_answer

The equivalent capacitance between P and Q in the given figure is lf if. Then the value of capacitance C will be :

A)                 \[1.2\mu F\]                      

B) \[3.6\mu F\]

C) \[2\mu F\]                                         

D) \[1.4\mu F\]

Correct Answer: D

Solution :

                 Equivalent capacitance of \[2.5\mu F\] and \[1\mu F\]which are conceded in parallel is \[{{C}_{P}}=2.5+1=3.5\] Now \[{{C}_{P}}\] and C are connected in series so equivalent capacitance, \[{{C}_{PQ}}=\frac{C\times 3.5}{C+3.5}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1=\frac{C\times 3.5}{C+3.5}\] or        \[C+3.5=3.5C\] or     \[2.5C=3.5\]   or   \[C=1.4\mu F\]