question_answer

For the circuit shown in figure,

A)  resistance \[R=46\Omega \]

B)  current through \[20\Omega \] resistance is 0.1A

C)  potential difference across the mi resistance is 2V

D)  All of the above are true

Correct Answer: D

Solution :

 \[\frac{1}{R}=\frac{1}{10}+\frac{1}{10}+\frac{1}{10}\] \[\Rightarrow \] \[\Rightarrow \] \[R=\frac{20}{5}=4\Omega \] Now, using Ohms law, \[i=\frac{25}{R+R}\] \[\Rightarrow \] \[0.5=\frac{25}{R+4}\] \[\Rightarrow \] \[R+4\frac{25}{0.5}\] \[\Rightarrow \] \[R=50-4-46\Omega \] Current through \[20\Omega \]resistor \[=\frac{0.5\times 5}{20+5}=\frac{2.5}{25}=0.1A\] Potential difference across middle resistor = Potential difference across \[20\Omega \] \[=20\times 0.1=2V\]