Name some prominent scientists who have made significant contributions to the study of wave physics.

$A$ source of light emits a continuous stream of light energy which falls on a given area. Luminous intensity is defined as

$A$ 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:

In interference and diffraction, the light energy is redistributed. If it reduces in one region, producing a dark fringe, it increases in another region, producing a bright fringe. Statement $A$: As there is no gain or loss of energy, these phenomena are consistent with the principle of conservation of energy. Statement $B$: Diffraction and interference are characteristics exhibited only by light waves. Choose the correct answer from the options given below:

Fraunhofer lines are produced by the absorption of light in

Statement $(S)$: Using Huygen's eye-piece,measurements can be taken but are not correct.
Reason $(R)$: The cross wires,scale,and final image are not magnified proportionately because the image of the object is magnified by two lenses,whereas the cross-wire scale is magnified by one lens only.
Identify the correct option from the following: