Correct Option
The correct option is (a) 1 only.
Explanation
Sound is a mechanical wave that propagates through a medium. It is fundamentally a form of energy generated by the vibration of objects, which creates pressure variations in the surrounding medium.
Statement-wise Analysis
- Statement 1 is Correct: Sound is a form of energy that produces the sensation of hearing. It is generated when an object vibrates and transmits energy through a medium (solid, liquid, or gas) to the receiver's ear.
- Statement 2 is Incorrect: The production of sound strictly requires the utilization of energy. According to the law of conservation of energy, energy is transformed from one form to another. For instance, mechanical energy used to strike a drum or pluck a guitar string is converted into sound energy. It is impossible to produce sound without an input of energy.
- Statement 3 is Incorrect: Vibration is defined as the rapid to-and-fro or back-and-forth motion of an object about a central equilibrium position. It is an oscillatory motion, not a unidirectional (one-way) motion.
Key Takeaway: Sound is a form of energy produced by the oscillatory (to-and-fro) motion of particles, known as vibration, and always requires an external energy source for its generation.