Calculating the resistance question
When a resistor of resistance 40 ohm is connected in parallel with the resistance of a circuit,the current is tripled.What is the resistance of the circuit in the absence of the 40 ohm resistor ? (answer given is 80 ohms) Ok,so when the 40 ohm resistor is directly connected to the circuit ,a current 'I' passes through it .
When the resistors are connected in parallel,the total current is now 3'I' so... a current 'I' would pass through the 40 ohm resistor and a current of 2I through resistor R,right?
Assuming it is so,
(In the 2nd situation )by equating the potential differences of the resistors in parallel ,
V= IR
=I*40 = 2I*R
I get R=20 ohm
I can't seem to figure out where I've gone wrong.hope you can help.
Thank you.
