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.

$A$ zone plate of focal length $60\,cm$ behaves as a convex lens. If the wavelength of incident light is $6000\,\mathring{A},$ then the radius of the first half-period zone will be:

Light from a point source falls on a small area placed perpendicular to the incident light. If the area is rotated about the incident light by an angle of $60^o$,by what fraction will the illuminance change?

Write the difference between the interference pattern and diffraction pattern.

Assertion: The colour of the green flower seen through red glass appears to be dark.
Reason: Red glass transmits only red light.

Two point monochromatic and coherent sources of light of wavelength $\lambda$ are placed on the dotted line in front of a large screen. The sources emit waves in phase with each other. The distance between $S_1$ and $S_2$ is $d$,while their distance from the screen is much larger. Then,
$(1) \rightarrow$ If $d = 7\lambda / 2$,$O$ will be a minima.
$(2) \rightarrow$ If $d = 4.3\lambda$,there will be a total of $8$ minima on the $y$-axis.
$(3) \rightarrow$ If $d = 7\lambda$,$O$ will be a maxima.
$(4) \rightarrow$ If $d = \lambda$,there will be only one maxima on the screen.
Which is the set of correct statements?