The force between two charges is 10 N in vacuum. If a dielectric of constant 5 is inserted, force becomes MCQ with Answer and Explanation

Explanation:
Micron or micrometer = 10⁻⁶ m.

Explanation:
Apparent weight = m(g+a) = 60×(10+2) = 720 N, which corresponds to 72 kg mass on scale (if scale calibrated in kg under g=10). Reading 72 kg. Downward acceleration would reduce.

Explanation:
Critical angle θ_c for total internal reflection: sinθ_c = n₂/n₁, where n₁ > n₂. Here n₁=1.5 (glass), n₂=1 (air), so sinθ_c = 1/1.5 = 2/3 ≈ 0.6667 ⇒ θ_c = sin⁻¹(0.6667) ≈ 41.8° ≈ 42°. Memory aid: 'sinθ_c = 1/n for glass to air'. This calculation tests understanding of total internal reflection conditions, crucial for optics in competitive exams. Always ensure light travels from denser to rarer medium for TIR to be possible; otherwise, no critical angle exists.