If a spring has time period $$T,$$ and is cut into $$n$$ equal parts, then the time period of each part will be

In a simple harmonic oscillator, at the mean position

A child swinging on a swing in sitting position, stands up, then the time period of the swing will

length of a string tied to two rigid supports is $$40$$ $$cm$$. Maximum length (wavelength in $$cm$$) of a stationary wave produced on it is