A 100 W bulb is used for 10 hours. Energy consumed is MCQ with Answer and Explanation

Explanation:
RADAR uses microwaves (short wavelength radio waves). Often classified as microwaves.

Explanation:
When B starts, A has already traveled 10 m/s × 2 s = 20 m. Relative velocity of B w.r.t A = 15 - 10 = 5 m/s. Time to cover 20 m gap at 5 m/s relative speed = 20/5 = 4 s after B starts. Since B started 2 s late, total time from A's start = 2 + 4 = 6 s. Alternatively, equate distances: 10t = 15(t-2) ⇒ 10t = 15t - 30 ⇒ t = 6 s. This relative motion approach simplifies pursuit problems. Memory tip: In same-direction motion, use relative velocity = |v₁ - v₂|. Frequently tested in kinematics sections of competitive exams.

Explanation:
Elastic collisions conserve both total momentum and total kinetic energy. Inelastic collisions conserve only momentum. This distinction is fundamental in collision analysis. Memory aid: 'Elastic = KE + momentum conserved; Inelastic = momentum only'. Frequently tested concept to differentiate collision types in competitive exam mechanics sections.