Q113 / 150 · MHT CET 2026 (18 April Shift 1) · Physics

A diode and resistance are connected as shown in figures.
Figure
Out of the following statements, which one is true?
Diode in
A) fig (1) and fig (2) are both forward biased.
B) fig (1) and fig (2) are both reverse biased.
C) fig (1) is forward biased and in fig (2) is reverse biased.
D) fig (1) is reverse biased and in fig (2) is forward biased.

  • Correct answer
    A
    D
  • B
    B
  • C
    A
  • D
    C

Solution

A diode is said to be forward biased if the potential at its p-side is greater than the potential at its n-side ($V_p > V_n$). It is reverse biased if the potential at its p-side is less than the potential at its n-side ($V_p < V_n$).

In Figure 1:
The p-side of diode $D_1$ is connected to $-5\text{ V}$ and the n-side is connected to $-3\text{ V}$ through resistor $R_1$.
Since $-5\text{ V} < -3\text{ V}$, the p-side is at a lower potential than the n-side.
Therefore, diode $D_1$ is reverse biased.

In Figure 2:
The p-side of diode $D_2$ is connected to $0\text{ V}$ and the n-side is connected to $-4\text{ V}$ through resistor $R_2$.
Since $0\text{ V} > -4\text{ V}$, the p-side is at a higher potential than the n-side.
Therefore, diode $D_2$ is forward biased.

Thus, the diode in fig (1) is reverse biased and in fig (2) is forward biased.

Answer: D

Hence, the correct answer is option: 'A'.

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