Diffraction demonstrates light's: MCQ with Answer and Explanation

Explanation:
Diamagnets: χ ≈ -10⁻⁵ (small negative), weakly repelled by magnetic fields. Paramagnets: small +χ; Ferromagnets: large +χ. Memory tip: 'Diamagnetic: χ < 0, weak repulsion'. Magnetism classification frequently tested in competitive exams.

Explanation:
Methane (CH₄) is primary component. LPG is mainly propane and butane. CNG is compressed methane. This relates to everyday physics and chemistry.

Explanation:
Work done is given by W = F * d * cos(theta). In uniform circular motion, the centripetal force is always directed strictly towards the center of the circle, while the instantaneous displacement (velocity vector) is tangential to the circle. The angle (theta) between them is exactly 90 degrees. Since cos(90) = 0, the work done by the centripetal force is always zero.