Period T = 2π√(m/k) = 2π√(5/200) = 2π√(1/40) = 2π × (1/(2√10)) = π/√10 ≈ π s (approximately).

Due to refraction at the water-air interface, light bends as it exits water. This causes objects to appear at different positions and moving at different speeds than they actually are—an optical illusion, not actual motion change.

From orbital mechanics: v = √(GM/r). If r becomes 2r, then v_new = √(GM/2r) = v/√2. Velocity decreases by factor √2.

Energy of photon: E = hf = 6.63 × 10⁻³⁴ × 5 × 10¹⁴ = 3.315 × 10⁻¹⁹ J ≈ 2.07 eV. KE_max = E - φ = 2.07 - 2 = 0.07 eV. (Recalculation shows approximately 2.08 eV with more precision.)

Acoustic impedance (Z) = ρ × c, where ρ is density and c is sound velocity. SI unit is kg/(m²·s). It's crucial for understanding sound reflection and transmission.

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.

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.