Question

Three resistors of 1 ohm , 2 ohm and 4 ohm are connected in parallel in a circuit. If a 1 ohm resistor draws a current of 1 A , find the current through the other two resistors​

Answer 1

Key Points :

• Current across resistors in series combination is same
• Voltage across resistors in series combination varies
• Current across resistors in parallel combination varies
• Voltage across resistors in parallel combination is same

Individual sum of current across the resistors is equals to the net current across the circuit

Solution :

1 Ω resistor draws a current of 1 A ( parallel combination )

Apply Ω's law ,

⇒ V = IR

⇒ V (1)(1)

⇒ V = 1 V  $\pink{\bigstar}$

Now , this voltage across all resistors is same ( ∵ parallel combination ).

Current across 2 Ω resistor ,

⇒ V = IR

⇒ (1) = I (2)

⇒ I = ¹/₂

⇒ I = 0.5 A  $\blue{\bigstar}$

Current across 4 Ω resistor ,

⇒ (1) = I (4)

⇒ I = ¹/₄

⇒ I = 0.25 A  $\green{\bigstar}$