The weight of a body at Earth's centre is MCQ with Answer and Explanation

Explanation:
Parallel branches share same voltage (potential difference). Current divides inversely with resistance. Memory aid: 'Parallel: same voltage; Series: same current'. Fundamental circuit property frequently tested in competitive exams to assess basic electronics understanding.

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:
Electromagnetic waves are transverse: electric field (E) and magnetic field (B) are perpendicular to each other and both perpendicular to the direction of wave propagation. This is a fundamental property derived from Maxwell's equations. Memory tip: 'EM waves: E ⊥ B ⊥ propagation direction; right-hand rule for orientation'. This conceptual question tests electromagnetic wave fundamentals, crucial for modern physics in competitive exams. Always recall that EM waves require no medium and travel at speed of light in vacuum.