Weight of an object on the Moon is about _____ of its weight on Earth. MCQ with Answer and Explanation

Explanation:
Acceleration a = dv/dt = d(3t² + 2t)/dt = 6t + 2. At t = 2 s: a = 6(2) + 2 = 14 m/s². Differentiation of velocity gives instantaneous acceleration. Memory tip: a = dv/dt; for polynomial v(t), differentiate term by term. Tests calculus application in kinematics, common in advanced competitive exam questions.

Explanation:
Polarization requires transverse waves (oscillations perpendicular to propagation). Light, radio waves, X-rays are electromagnetic transverse waves and can be polarized. Sound waves in air are longitudinal (oscillations parallel to propagation) and cannot be polarized. Memory tip: 'Polarization ⇒ transverse waves only; sound is longitudinal ⇒ no polarization'. This wave property question tests understanding of wave types, frequently examined in competitive exams. Always classify waves as transverse/longitudinal to determine polarization possibility; this is a common conceptual trap.

Explanation:
Power P = 1/f (in metre). f = 1/P = 1/2 = 0.5 m = 50 cm. Positive power indicates convex lens. For concave lens, power negative. Dioptre (D) is SI unit of power. Remember f in metres.