NEET2019PhysicsCurrent ElectricityActual
Six similar bulbs are connected as shown in the figure with a DC source of emf E , and zero internal resistance. The ratio of power consumption by the bulbs when i all are glowing and ii in the situation when two from section A and one from section B are glowing will be,
Options
- A4 : 9
- B9 : 4
- C1 : 2
- D2 : 1
Correct answer
B. 9 : 4
Step-by-step solution
Case (i): When all bulbs are glowing, then, R eq = 2 3 R Then, initially power consumption will be from the equation, Power P   =   E 2 R P i = E 2 R e q = 3   E 2 2   R     . . . 1 Case (ii): When two bulbs in section A and one bulb in the section are glowing, R eq ' = R 2 + R = 3 2 R P f = E 2 R eq ' = 2 E 2 3 R   . . . 2 From above two equations, ratio of power is, P i P f = 9 4