P-N Junction Diode question from MHT CET 2024 (3 May, Shift 1)

Answer: (a)

1. The $4$ V cell (positive towards A) tries to drive current from right to left, and the $1$ V cell (positive towards B) from left to right.
2. Net emf $= 4 - 1 = 3$ V, which drives current from right to left.
3. The diode points from left to right, so for this current it is reverse biased.
4. An ideal reverse biased diode allows no current, so $I = 0$.
5. So the answer is (a) zero ampere.