Using F = ma: a = F/m = 10/2 = 5 m/s². Using v² = u² + 2as: v² = 0 + 2(5)(5) = 50. v = √50 ≈ 7.07 m/s. Checking options again using work-energy: Work = KE; 10×5 = (1/2)(2)v²; v = 5√2 m/s. The closest correct approach gives v² = 50, so v = 5√2 m/s or approximately 7.07 m/s. Option B matches √50.

The Lyman series involves transitions to n=1 from higher energy levels. Balmer series ends at n=2, Paschen at n=3, and Brackett at n=4.

Charge Q = I × t, where I = 5 A and t = 10 s. Q = 5 × 10 = 50 Coulombs.

Centripetal acceleration a = v²/r = (10)²/5 = 100/5 = 20 m/s².

Refractive indices: Air ≈ 1, Water ≈ 1.33, Glass ≈ 1.5, Diamond ≈ 2.42. Diamond has the highest refractive index among these options.

For capacitors in series: 1/C = 1/C₁ + 1/C₂ = 1/2 + 1/3 = 5/6. Therefore C = 6/5 = 1.2 μF.

At maximum height, v = 0. Using v² = u² - 2gh: 0 = 20² - 2(10)h. 20h = 400. h = 20 m.

The Second Law of Thermodynamics states that entropy of an isolated system increases or remains constant. Heat spontaneously flows from hot to cold, not vice versa, establishing the direction of processes.

Kinetic energy KE = (1/2)mv². When velocity is doubled: KE' = (1/2)m(2v)² = (1/2)m(4v²) = 4 × (1/2)mv² = 4K.

The photoelectric effect occurs when light of frequency greater than or equal to the threshold frequency strikes a metal surface, causing electron emission. It demonstrates the particle nature of light.