In the circuit diagram D1, D2, D3 and D4 are diodes. Choose the correct answer from the options given below
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → D1 and D3 are forward biased
A diode is forward biased when its p-side (the triangle of the symbol) is at a higher potential than its n-side (the bar). The top junction is connected to the positive terminal and the bottom junction to the negative terminal; the left and right junctions are joined through the \( 2\,\Omega \) resistor.
D1 (top to right): its triangle is at the positive top junction and its bar towards the right junction, so it is forward biased.
D2 (left to top): its bar is at the positive top junction, so its n-side is at the higher potential; it is reverse biased.
D3 (left to bottom): its bar is at the negative bottom junction, so its p-side is higher; it is forward biased.
D4 (bottom to right): its triangle is at the negative bottom junction, so its p-side is lower; it is reverse biased.
The current flows from + through D1, then through the \( 2\,\Omega \) resistor from right to left, and back through D3 to −. So D1 and D3 are forward biased.
NCERT (2026-27):
p-n Junction Diode Under Forward Bias – “When an external voltage V is applied across a semiconductor diode such that p-side is connected to the positive terminal of the battery and n-side to the negative terminal [Fig. 14.13(a)], it is said to be forward biased.”