The moderator used in a nuclear reactor serves to MCQ with Answer and Explanation

Explanation:
Planck's constant (h) has dimensions [ML²T⁻¹]. Angular momentum (L = mvr) has dimensions [M][LT⁻¹][L] = [ML²T⁻¹], matching exactly. Linear momentum is [MLT⁻¹], force is [MLT⁻²], and torque is [ML²T⁻²]. This dimensional equivalence is fundamental in quantum mechanics, linking wave-particle duality. Memory tip: Both represent 'action' quantities with identical dimensional structure. This concept frequently appears in competitive exams testing dimensional analysis skills.

Explanation:
d = v × t / 2 = 340 × 3 / 2 = 510 m.

Explanation:
Escape velocity (Ve) is the minimum velocity needed to overcome Earth's gravitational pull so that final velocity at infinity is zero. If launched with velocity v > Ve, the body will escape and, due to conservation of energy, retain a residual speed (v_infinity) at an infinite distance, calculated by v_infinity = √(v² - Ve²). Here, v = 2Ve, so it retains speed.