Question

Amplitude of vibrations remains constant in case of
(i) Free vibrations
(ii) Damped vibrations
(iii) Maintained vibrations
(iv) Forced vibrations

• A. $\left(i\right),\left(iii\right)\text{and}\left(iv\right)$
• B. $\left(ii\right)\text{and}\left(iii\right)$
• C. $\left(i\right),\left(ii\right)\text{and}\left(iii\right)$
• D. $\left(ii\right)\text{and}\left(iv\right)$

Answer 1

The correct option is A $\left(i\right),\left(iii\right)\text{and}\left(iv\right)$

In free vibrations, amplitude of vibrations remains constant as there are no resistive forces in the medium. Ideally free vibrations are possible in vacuum.

In damped vibrations, amplitude of vibrations decreases with increase in time as $A=A_0{e}^{-bt}$. So the amplitude is decreasing exponentially with time.

In maintained vibrations, since the energy is supplied to the oscillator at the same rate at which it is dissipated, amplitude of oscillations remains unchanged.

In forced oscillations, amplitude of vibrations remains constant as the external periodic force provides sufficient energy to maintain the amplitude of oscillations.

Thus, option (a) is the correct answer.