$A$ simple pendulum is set into vibrations. The bob of the pendulum comes to rest after some time due to

If the amplitude of a damped harmonic oscillator becomes half of its initial amplitude in a time of $10 \ s$, then the time taken for the mechanical energy of the oscillator to become half of its initial mechanical energy is (in $s$)

What is resonance? Give its example.

What is pure simple harmonic oscillation? Why is it not $100 \%$ possible in practice?

If a simple pendulum has significant amplitude (up to a factor of $1/e$ of original) only in the period between $t = 0 \ s$ to $t = \tau \ s$,then $\tau$ may be called the average life of the pendulum. When the spherical bob of the pendulum suffers a retardation (due to viscous drag) proportional to its velocity with $b$ as the constant of proportionality,the average life time of the pendulum is (assuming damping is small) in seconds:

In the case of a forced vibration,the resonance curve becomes very sharp when the