Assertion : We cannot meausre that potential barrier of p-n junction by putting a sensitive voltmeter across its terminals.
Reason: In the depletion layer, there are no free elctrons or holes and in the absence of forward bias, it offers, infinite, resistance.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true but the reason is not the correct explanation of the assertion
C. If assertio is true statement but reason is false.
D. If both assertion and reason are false statement

Explanation

To solve the assertion and reason question regarding the potential barrier of a p-n junction, we can break it down into a step-by-step analysis.

### Step 1: Understand the Assertion
The assertion states that we cannot measure the potential barrier of a p-n junction by placing a sensitive voltmeter across its terminals. This is true because the p-n junction has a built-in potential barrier that prevents current flow in the absence of an external voltage.

**Hint for Step 1:** Consider what a potential barrier is and how it affects current flow in a p-n junction.

### Step 2: Analyze the Reason
The reason provided states that in the depletion layer of the p-n junction, there are no free electrons or holes. This is also true. The depletion region is formed when the p-type and n-type materials are joined, and the free charge carriers recombine, leaving behind a region devoid of charge carriers.

**Hint for Step 2:** Reflect on the characteristics of the depletion layer and its role in the behavior of the p-n junction.

### Step 3: Evaluate the Resistance in the Depletion Layer
The reason further explains that in the absence of forward bias, the depletion layer offers infinite resistance. This means that no current can flow through the junction without an external voltage applied. Thus, a voltmeter would not be able to measure any potential difference across the terminals.

**Hint for Step 3:** Think about how resistance affects the measurement of voltage and the implications of infinite resistance.

### Step 4: Conclusion on Assertion and Reason
Since both the assertion and the reason are correct, and the reason explains the assertion, we can conclude that both statements are true and that the reason supports the assertion.

**Hint for Step 4:** Consider how the relationship between the assertion and reason affects the overall validity of the statements.

### Final Answer
Both the assertion and reason are correct, and the reason correctly explains the assertion. Therefore, we cannot measure the potential barrier of a p-n junction using a sensitive voltmeter due to the infinite resistance of the depletion layer in the absence of forward bias.