The force acting on a particle of mass 1 kg moving in a circle of radius 0.5 m with speed 2 m/s is MCQ with Answer and Explanation

Explanation:
Snell's law: n₁ sin i = n₂ sin r. 1×0.5 = 1.5 sin r => sin r = 0.5/1.5 = 1/3 ≈ 0.3333 => r ≈ 19.47°. So A.

Explanation:
A lactometer is a specific type of hydrometer used to test the purity of milk by measuring its relative density. All hydrometers, including lactometers, work on Archimedes' Principle of buoyancy. They float at a depth that depends directly on the density of the liquid; they sink deeper in less dense liquids (like milk heavily diluted with water).

Explanation:
Hertz (Hz) = cycle per second = s⁻¹. Named after Heinrich Hertz. For sound, radio waves. Kilohertz, megahertz, gigahertz.