question_answer

The circuit shown in the figure contains three diodes each with forward resistance of 50\[\Omega \] and with infinite backward resistance. If the battery voltage is 6 V, the current through the 100 \[\Omega \] resistance is

A)  zero                                     

B)  36 mA

C)  43 mA                                 

D)  50 mA

Correct Answer: B

Solution :

                 According to the given polarity, diode \[{{D}_{1}}\] and \[{{D}_{2}}\] are forward biased while \[{{D}_{3}}\] is revers biased. Hence current will pass through \[{{D}_{1}}\] and \[{{D}_{2}}\]only. Total restiance in drcuit.                 \[R=\frac{100\times 200}{200+100}+100\]                 \[R=\frac{200}{3}+100=\frac{500}{3}\] \[\therefore \] Current, \[i=\frac{6}{\frac{500}{3}}=\frac{18}{500}=36\times {{10}^{-3}}\]                                 = 36 mA