Q209 / 240 · KCET 2026 · Physics
In which of the following figures, diode is reverse biased?
- A
- Correct answerB
- C
- D
Solution
A diode is reverse biased when the potential at its p-side (anode) is less than the potential at its n-side (cathode), i.e., $V_p < V_n$.
Let us check the potentials for each given figure:
For option (A):
$V_p = 5\text{ V}$ and $V_n = 0\text{ V}$ (grounded).
Since $V_p > V_n$, the diode is forward biased.
For option (B):
$V_p = -20\text{ V}$ and $V_n = -10\text{ V}$.
Since $V_p < V_n$ ($-20\text{ V} < -10\text{ V}$), the diode is reverse biased.
For option (C):
$V_p = 15\text{ V}$ and $V_n = 10\text{ V}$.
Since $V_p > V_n$, the diode is forward biased.
For option (D):
$V_p = 20\text{ V}$ and $V_n = -5\text{ V}$.
Since $V_p > V_n$, the diode is forward biased.
Thus, the diode in option (B) is reverse biased.
Answer:
Let us check the potentials for each given figure:
For option (A):
$V_p = 5\text{ V}$ and $V_n = 0\text{ V}$ (grounded).
Since $V_p > V_n$, the diode is forward biased.
For option (B):
$V_p = -20\text{ V}$ and $V_n = -10\text{ V}$.
Since $V_p < V_n$ ($-20\text{ V} < -10\text{ V}$), the diode is reverse biased.
For option (C):
$V_p = 15\text{ V}$ and $V_n = 10\text{ V}$.
Since $V_p > V_n$, the diode is forward biased.
For option (D):
$V_p = 20\text{ V}$ and $V_n = -5\text{ V}$.
Since $V_p > V_n$, the diode is forward biased.
Thus, the diode in option (B) is reverse biased.
Answer:
Hence, the correct answer is option: 'B'.