Work done by centripetal force in circular motion is: MCQ with Answer and Explanation

Explanation:
Work done is given by W = F * d * cos(theta). In uniform circular motion, the centripetal force is always directed strictly towards the center of the circle, while the instantaneous displacement (velocity vector) is tangential to the circle. The angle (theta) between them is exactly 90 degrees. Since cos(90) = 0, the work done by the centripetal force is always zero.

Explanation:
Polarization (restriction of electric field oscillation to one plane) is possible only for transverse waves, where oscillations are perpendicular to propagation direction. Longitudinal waves (e.g., sound) cannot be polarized as oscillations are along propagation. This was key evidence for light's transverse wave nature. Memory aid: 'Polarization ⇒ transverse wave; light is EM transverse wave'. This conceptual question tests wave optics fundamentals, frequently examined in competitive exams. Always distinguish wave types: transverse (light, string waves) vs longitudinal (sound, spring waves).

Explanation:
Torricelli's Law is a direct application of Bernoulli's principle. It proves mathematically that the velocity of fluid exiting a small hole (efflux velocity v) is v = sqrt(2gh). This is exactly the same velocity a solid body would acquire if it fell freely under gravity from rest over the same vertical height 'h'.