Question

Given below are two statements:
Assertion (A): In Kronig Penney model, if the barrier is weak there will be narrow energy gaps.
Reason (R): For weak barrier, transmission is almost equal to one.

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R is not the correct explanation of A
• C. A is correct but R is not correct
• D. A is not correct but R is correct

Hint:

In the Kronig-Penney model, weak barriers give narrow band gaps, while strong barriers give wider band gaps.

Answer 1

The Correct Option is A

Concept:
Kronig-Penney model explains the formation of allowed energy bands and forbidden energy gaps in a periodic potential.

Step 1: Check Assertion.
If the barrier is weak, electrons can pass through the periodic potential more easily. Therefore, the forbidden energy gaps become narrow. \[ A \text{ is correct} \]

Step 2: Check Reason.
For weak barrier, transmission is almost equal to one. This means electrons can pass through the barrier easily. \[ R \text{ is correct} \]

Step 3: Check explanation.
High transmission through weak barriers leads to narrow energy gaps. Therefore, Reason correctly explains Assertion. \[ \therefore \text{Correct Answer is (A)} \]