JEE MainPhysicsCurrent Electricity
Three identical resistors, each having a resistance of 12 and a maximum safe power rating of 3 W , are connected in a circuit. Two of these resistors are connected in parallel, and this combination is connected in series with the third resistor. What is the maximum safe voltage that can be applied across the entire combination without exceeding the power rating of any individual resistor?
Options
- A9 V
- B12 V
- C18 V
- D6 V
Correct answer
A. 9 V
Step-by-step solution
The maximum safe current that can flow through a single resistor is given by: I_ max = P R = 3 12 = 0.25 = 0.5 A In the given configuration, two resistors are in parallel, and the third is in series with them. The total current of the circuit flows through the series resistor, while it splits equally between the two parallel resistors. Therefore, the series resistor will reach its maximum current limit first and acts as the bottleneck. The maximum total current the circuit can safely draw is I_ total = 0.5 A . The