Three 2Ω resistors A, B and C are connected as shown in figure. Each of them dissipates energy and can with stand a maximum power of 18 W without melting. Find the maximum current that can flow through the three resistors.
OR
Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 2Ω in series with a combination of two resistors (4Ωeach) in parallel and a voltmeter across the parallel combination. Will the potential difference across the 2Ωresistor be same as that across the parallel combination of 4Ω resistors? Give reason.
Power dissipated by the resistor of 2 ohm (P) = i2R (where i is the current through the resistor and R is the resistance of the resistor.)
Therefore: i2 = P/R =(18/2) A = 9A
⇒ i= 3A
Resistances B and C are connected in parallel, therefore, the current is equally divided in between them i.e. 1.5A.
OR
The effective resistance across the resistors of 4 ohm connected in parallel is:
Req= 
The resistance is equal hence same current will flow through these. Hence the potential difference across the parallel combination and the 2Ω resistor is the same.