question_answer

The voltage drop across a forward biased diode is 0.7 volt. In the following circuit, the voltages across the 10 ohm resistance in series with the Diode and 20 ohm resistance are:

A) \[0.70\operatorname{V},4.28\operatorname{V}\]  

B) \[3.58\operatorname{V},4.28\operatorname{V}\]

C) \[5.35\operatorname{V},2.14\operatorname{V}\]  

D) \[3.58\operatorname{V},9.3\operatorname{V}\]

Correct Answer: B

Solution :

[b]

\[\frac{x-10}{20}+\frac{x-0}{10}+\frac{x-9.3}{10}=0\]

\[x-10+2x+2x-18.6=0\Rightarrow 5x=28.6\]

\[x=\frac{28.6}{5}=5.72V\]

\[{{\operatorname{V}}_{10\Omega }}=9.3-5.72=3.58\]

\[{{\operatorname{V}}_{20\Omega }}=10-5.72=4.28\]