Concepts Of Physics MCQ Edition [Volume 2]PhysicsSemiconductors and Semiconductor Devices
Determine the currents passing through the resistances in the circuits depicted in the figure.
Options
- A(a) 1 A , (b) 0 , (c) 1 A , (d) 1 A
- B(a) 0 , (b) 1 A , (c) 1 A , (d) 1 A
- C(a) 1 A , (b) 0 , (c) 0 , (d) 1 A
- D(a) 1 A , (b) 1 A , (c) 1 A , (d) 0
Correct answer
A. (a) 1 A , (b) 0 , (c) 1 A , (d) 1 A
Step-by-step solution
Assuming the diodes to be ideal, they act as short circuits when forward-biased and open circuits when reverse-biased. In circuit (a), both diodes are forward-biased as their p-sides are connected towards the positive terminal of the battery. They act as short circuits. The current is I_a = V R = 2 2 = 1 A . In circuit (b), the first diode is forward-biased but the second diode is reverse-biased. The reverse-biased diode acts as an open circuit, breaking the series circuit. Thus, the current is I_b = 0 . In circuit