Question

Given below are two statements:
Assertion (A): The quantum of energy of an elastic wave is called phonon.
Reason (R): The energy of each phonon is \(\epsilon=h\nu\).

• 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:

Phonon is the quantum of lattice vibration, just as photon is the quantum of electromagnetic radiation.

Answer 1

The Correct Option is A

Concept:
A phonon is the quantum of lattice vibration or elastic wave in a crystal.

Step 1: Check Assertion.
Elastic waves in solids are quantized. The quantum of such vibrational energy is called a phonon. \[ A \text{ is correct} \]

Step 2: Check Reason.
The energy of a phonon is: \[ \epsilon=h\nu \] where \(\nu\) is the frequency of vibration. \[ R \text{ is correct} \]

Step 3: Check explanation.
Since a phonon represents a quantum of vibrational energy and its energy is \(h\nu\), Reason explains Assertion. \[ \therefore \text{Correct Answer is (A)} \]