Write the difference between the interference pattern and diffraction pattern.

The figure shows $P$ and $Q$ as two equally intense coherent sources emitting radiations of wavelength $20 \, m$. The separation $PQ$ is $5.0 \, m$ and the phase of $P$ is ahead of the phase of $Q$ by $90^{\circ}$. $A, B,$ and $C$ are three distant points of observation equidistant from the mid-point of $PQ$. The intensity of radiations at $A, B,$ and $C$ will bear the ratio:

$A$ source emits light of wavelengths $4700 \ \mathring{A}$,$5400 \ \mathring{A}$,and $6500 \ \mathring{A}$. The light passes through red glass before being tested by a spectrometer. Which wavelength is seen in the spectrum?

$A$ circular disc of which $2/3$ part is coated with yellow and $1/3$ part is with blue. It is rotated about its central axis with high velocity,then it will be seen as

The figure shows a schematic diagram of the arrangement of Young's Double Slit Experiment. Choose the correct statement$(s)$ related to the wavelength of light used.

Compare and contrast the interference and diffraction.