In p-n junction diode, near junction holes combine with electrons, and impurity ions form a barrier potential which opposes the recombination of electron-hole pairs. Value of barriers potential for Si is 0.7 volt and for Ge is 0.3 V. thus charge density at the junction becomes zero and an electric field is produced near junction. this region is called depletion layer. Thickness of depletion layer is of the order of `10^(-6)` meter. in forward bias p terminal is connected with the positive terminal of cell and n is connected with negative terminal of cell and n is connected with negative terminal of cell. as forward voltage is increased, current increases exponentially.
As forward voltage is increased barrier potential in p-n junction diode is

A. increased
B. Decreased
C. remain same
D. nothing can be said.

Options

A. Increased
B. Decreased
C. Remains same
D. nothing can be said

Answer

To solve the question about the behavior of the barrier potential in a p-n junction diode when forward voltage is increased, we can follow these steps:

### Step 1: Understand the concept of barrier potential
The barrier potential in a p-n junction diode is the voltage that must be overcome for current to flow through the diode. For silicon (Si), this value is approximately 0.7 volts, and for germanium (Ge), it is about 0.3 volts. This potential is created due to the recombination of charge carriers (holes and electrons) near the junction.

**Hint:** Remember that the barrier potential is a result of the electric field created by the charge separation at the junction.

### Step 2: Analyze the effect of forward bias
In forward bias, the p-type material is connected to the positive terminal of a battery, and the n-type material is connected to the negative terminal. This configuration reduces the barrier potential, allowing current to flow more easily.

**Hint:** Think about how connecting the p-side to a higher potential affects the energy levels at the junction.

### Step 3: Increase in forward voltage
As the forward voltage is increased, the potential on the p-side increases. This increase in potential effectively lowers the height of the potential barrier, making it easier for electrons to move from the n-side to the p-side and for holes to move from the p-side to the n-side.

**Hint:** Consider how increasing the voltage impacts the energy landscape of the diode.

### Step 4: Conclusion about the barrier potential
Since the barrier potential is reduced when the forward voltage is increased, we can conclude that the barrier potential decreases as the forward voltage increases.

**Hint:** Remember that the barrier potential is inversely related to the applied forward voltage in a p-n junction.

### Final Answer
The correct answer to the question is **B. Decreased**.