The process by which heat from the Sun reaches Earth is MCQ with Answer and Explanation

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.

Explanation:
A speedometer shows the speed of a vehicle at a particular instant in time. Speed is a scalar quantity (magnitude only, no direction). Therefore, it measures instantaneous speed. If it were measuring velocity, it would also need to display the car's current compass direction of travel at every moment.

Explanation:
Pendulum period T = 2π√(l/g) for small amplitudes. It depends on length l and gravity g, but not on bob mass or amplitude (isochronism for small angles). Mass independence arises because gravitational force and inertia both proportional to mass, canceling out. Memory aid: 'Pendulum: T ∝ √(l/g); independent of mass and small-amplitude'. This conceptual question tests oscillations fundamentals, frequently examined in competitive exams. Always verify the small-angle approximation; competitive exams assume it unless specified otherwise. This problem assesses understanding of which parameters affect periodic motion.