Which of the following materials is diamagnetic in nature? MCQ with Answer and Explanation

Explanation:
The distance covered in the nth second is Sn = u + a/2 * (2n - 1). For n=2: 12 = u + a/2 * (3) => 2u + 3a = 24. For n=4: 20 = u + a/2 * (7) => 2u + 7a = 40. Subtracting equations: 4a = 16 => a = 4 m/s^2. Substitute 'a' back: 2u + 3(4) = 24 => 2u = 12 => u = 6 m/s.

Explanation:
Myopic eye focuses image in front of retina. A diverging (concave) lens spreads light so image falls on retina. Hypermetropia (farsightedness) corrected by convex lens. Bifocals for presbyopia. Cylindrical for astigmatism.

Explanation:
Beta (β) rays are streams of high-speed electrons (β⁻) or positrons (β⁺) emitted during radioactive decay. Beta-minus decay: neutron → proton + electron + antineutrino. Alpha rays are helium nuclei (²He⁴); gamma rays are high-energy photons; neutrons are neutral particles. Memory tip: 'Beta = electrons; Alpha = He nucleus; Gamma = photons'. This classification question tests knowledge of radioactivity types, crucial for modern physics in competitive exams. Always distinguish penetration power: alpha < beta < gamma.