Question

Potential difference across 4$\Omega$ resistance.

Answer 1

Hint : Try to find current flowing in the circuit then use Ohm's Law for $4\Omega$ resistor.

Step 1 : Find equivalent resistance of the circuit.

Given: Two resistors of $8\Omega$ in parallel.

One resistance of $4\Omega$ in series with above combination.

Net resistance of two two resistors of $8\Omega$

$\frac{1}{R_{net}}=$ $\frac{1}{R_1}+\frac{1}{R_2}$

$\frac{1}{R_{net}}=$ $\frac{1}{8}+\frac{1}{8}$

$⟹$ $R_{net}=4\Omega$

Equivalent resistance of whole circuit

$R_{eq}=R_{4\Omega }+R_{net}$

$⟹$ $R_{net}=4\Omega +4\Omega =8\Omega$

Step 2 : Find current flowing in the circuit using Ohm's Law.

Ohm's Law for whole circuit $V=I{R}_{net}$

as $V=8V$ and $R_{net}=8\Omega$

$I=\frac{8V}{8\Omega }=1A$.

The same current is flowing throughout the circuit.

Step 3: Find potential difference across $4\Omega$ resistor.

Applying Ohm's Law for $4\Omega$ resistor we have

$V=I{R}_{4\Omega }$

$V=1A\times 4\Omega =4V$

Final Step : The potential difference across the $4\Omega$ resistor is $4V$.