It would be "resonance" that is occurring that causes the nonvibrating tuning fork <span>to begin to vibrate. Specifically the resonance of the sound waves that are traveling through air. </span>
When an object start vibrating with natural frequency which is also same as the external frequency which is produced then at this position the energy of source and the receiver becomes maximum and this is known as Resonance.
When resonance occurs in the system then system achieve its maximum stability and maximum energy state.
Here we know that a 256 Hz tuning fork is brought near other tuning fork of same frequency so since the frequency is same here so they both will achieve the condition of maximum energy.
