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
$20\Omega$ $=20\times 0.1=2V$