Question

In the given circuit through $10\Omega$ resistor is $2.5A$ value of $R$ is _____.

• A. $50\Omega$
• B. $40\Omega$
• C. $8\Omega$
• D. $10\Omega$

Answer 1

The correct option is C $8\Omega$

$i_1=2.5A$
Using the junction rule,

$i=i_1+i_2$

So voltage across $10\Omega$

$V_{10}=2.5\times 10=25$

And the voltage across $40\Omega$ will be the same as the $10\Omega$ resistance as they are in parallel.

$V_{40}=V_{10}=25V$

So, the value of the resistance $R$ connected in the circuit is:

$R=\frac{25}{i_1+i_2}$
$i_2=\frac{25}{40}A$
$\therefore R=8\Omega$