Three resistors of value 2r, 3r and 5r are connected in series with each other. The voltage source applied to this combination is 20 V. If the lowest resistance is 4 Ohms, what is value of current flowing through the circuit?

0.5 A 1 A 2.5 A 3 A

1 A

Reff = 2r + 3r + 5r = 10r lowest resistance = 2r = 4 Ohms Thus, r = 2 Ohms Reff = 10r = 10 (2 Ohms) = 20 Ohms I = V/Reff = 20 V/20 Ohms = 1 A