Question

What is the current if 12ohm and 40ohm resistors are connected in parallel and 12V potential difference is applied?​

Answer 1

• R1=12ohm
• R2=40ohm

We know

$\boxed{\sf \dfrac{1}{R}=\dfrac{1}{R_1}+\dfrac{1}{R_2}}$

$\\ \sf\longmapsto \dfrac{1}{R}=\dfrac{1}{12}+\dfrac{1}{40}$

$\\ \sf\longmapsto \dfrac{1}{R}=\dfrac{10+3}{120}$

$\\ \sf\longmapsto \dfrac{1}{R}=\dfrac{13}{120}$

$\\ \sf\longmapsto R=\dfrac{120}{13}$

$\\ \sf\longmapsto R=9.2\Omega$

• Potential difference=V=12V
• Current=I

suing ohms law

$\\ \sf\longmapsto \dfrac{V}{I}=R$

$\\ \sf\longmapsto I=\dfrac{V}{R}$

$\\ \sf\longmapsto I=\dfrac{12}{9.2}$

$\\ \sf\longmapsto I=1.3A$