Mention some examples of resonance.

Two pendulums $C$ and $D$ are suspended from a wire as shown in the given figure. Pendulum $C$ is made to oscillate by displacing it from its mean position. It is seen that $D$ also starts oscillating. What is the name of the phenomenon when the length of $D$ is made equal to $C$?

Name the phenomenon of sound observed in the following situation.

A vibrating fork is placed over the mouth of burette filled with water. The tap is opened and water level gradually falls. It is observed that the sound becomes the loudest for a particular length of air column.

Differentiate between resonance and forced vibrations.

The rearview mirror of a motor bike starts vibrating violently at some particular speed of the motor bike. What could be done to stop the violent vibrations ?

Resonance occurs when

In resonance,

A vibrating tuning fork is placed over the mouth of a burette filled with water. The tap is opened and the water level gradually falls. It is observed that the sound becomes the loudest for a particular length of air column.

What is the name of the phenomenon taking place when sound is produced for another length of air column and is not the loudest?

A vibrating tuning fork is placed over the mouth of a burette filled with water. The tap is opened and the water level gradually falls. It is observed that the sound becomes the loudest for a particular length of air column.

What is the name of the phenomenon taking place when this happens?

A sound wave of frequency $640 \mathrm{Hz}$ travels $800 \mathrm{m}$ in $2.5 \mathrm{s}$. The wavelength of the sound wave is _____ $\mathrm{m}$.