The radius of the central zone of a circular zone plate is $2.3\,mm$. The wavelength of the incident light is $5893\,\mathring{A}$. The source is at a distance of $6\,m$. What is the distance of the first image in meters?

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?

Red light differs from blue light in its

Write the difference between the interference pattern and diffraction pattern.

The maximum illumination on a screen at a distance of $2\, m$ from a lamp is $25\, lux.$ The value of total luminous flux emitted by the lamp is

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