यांत्रिक पृथक्करण किस पर लागू होता है? | Agrigyan

Option analysis:

• Correct physical calculation yields $40\text{ V}$.
• As per official NTA final key, Option 2 ($30\text{ V}$) is awarded.

In size reduction and milling engineering, Kick's law states that the energy required for producing analogous changes of reduction in size of geometrically similar bodies is proportional to the volume or mass of the body ($E = K_K \ln(L_1/L_2)$). Kick's law is based strictly on stress analysis of elastic deformation prior to fracture.

Option analysis:

• Kick's law: Correct, derived from the theory of elastic and plastic deformation within elastic limit.
• Rittinger's law: Based on the premise that energy consumed is proportional to the new surface area created.
• Bond's law: Based on crack-tip strain energy propagation ($E \propto 1/\sqrt{L_2} - 1/\sqrt{L_1}$).
• Planck's law: Governs blackbody spectral radiation, unrelated to milling.

In centrifugal disc-stack cream separators, the conical metal discs are stacked inside the bowl at an angle of inclination of $45^\circ$ to $60^\circ$ relative to the horizontal. This specific conical angle allows denser skim milk and sediment to slide down along the underside of the upper disc outward while lower-density fat globules coalesce and glide upward along the upper surface inward.

Option analysis:

• $11^\circ - 20^\circ$: Too shallow, sediment would stall and clog the disc channels.
• $45^\circ - 60^\circ$: Correct, optimal industrial range for self-clearing disc separation.
• $25^\circ - 40^\circ$: Sub-optimal inclination angle.
• $70^\circ - 80^\circ$: Excessively steep, drastically reduces sedimentation path area.