Question

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

Answer 1

Answer: (D)

$ \frac{1}{R}=\frac{1}{10}+\frac{1}{10}+\frac{1}{10} $
$ \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 $