Question

What is the current I in the given circuit (Fig.)?

Options

• 1.5 A

• 1.0 A

• \[\dfrac{2}{3} \mathrm{~A}\]

• none of these

Answer 1

1.5 A

Explanation:

The circuit forms a balanced Wheatstone bridge because all four outer resistors are 1 Ω. Hence, no current flows through the middle 5 Ω resistor.

Each branch has two 1 Ω resistors in series:

\[ R_1=R_2\]

\[= 1+1\]

\[=2\]

These two branches are connected in parallel.

\[ R=\frac{2\times2}{2+2}=1\,\Omega \]

Using Ohm’s law:

\[ I=\frac{V}{R}\]

\[ =\frac{1.5}{1} \]

\[ {=1.5\,A} \]