I am student of class 10 , I am in a competition

I will also be happy with recommendation of new ideas

 

Welcome to AAC!
Since this is a competition we don't give you a complete solution; just guidance. What have you come up with so far?

 

With no details about what kind of sound you are talking about or what kind of electrical energy you are talking about, about the only thing I can point out is that there is a whole class of devices that have been around for well over a century that are specifically designed to do this -- they are called microphones.

 

You need to do an energy estimate of how much energy is contained in a sound bite.
Compare that with the amount of electrical energy required to turn on an LED for one second.

 

What is your Project? What do you intend to demonstrate?

 

Is this an energy harvesting project?

 

An electrical 'generator' is generally made of a wire in some form moving through a magnet field, which converts the mechanical energy of motion into an electric potential.

The simplest way to convert sound into electrical energy is to use a loudspeaker as a large-area microphone.