The unit of magnetic field strength is MCQ with Answer and Explanation

Explanation:
Orbital velocity v = √(GM/r), where r is orbital radius from Earth's center. Thus v ∝ 1/√r. If r increases, v decreases. This follows from equating gravitational force to centripetal force: GMm/r² = mv²/r ⇒ v = √(GM/r). Higher orbits have slower speeds but longer periods. Memory aid: 'Higher orbit, slower speed' – counterintuitive but fundamental. This relationship is crucial for satellite motion questions in competitive exams. Always distinguish orbital velocity from escape velocity (which is √2 times orbital velocity at same radius).

Explanation:
Newton is a derived unit representing force, defined as kg·m/s². Kelvin (temperature), Ampere (current), and Mole (amount of substance) are fundamental SI units. Derived units are combinations of fundamental units through physical relationships. Newton comes from Newton's second law: F = ma. Memory aid: Remember the seven fundamental SI units: meter, kilogram, second, ampere, kelvin, mole, candela. All others like newton, joule, watt are derived. This distinction is essential for unit conversion questions in competitive exams.

Explanation:
Newton = kg·m/s², derived from base units. Kilogram, second, candela are base units. Derived units expressed in terms of base units. Joule, watt, pascal are also derived.