The energy of electron in ground state of hydrogen is -13.6 eV. Ionization energy is MCQ with Answer and Explanation

Explanation:
Sound travels to cliff and back. Total distance = speed × time = 340 × 2 = 680 m. So distance to cliff = 680/2 = 340 m. Use formula d = (v × t)/2. Time for round trip. Minimum distance for echo 17 m (approx) for 0.1 s persistence.

Explanation:
Maximum binding energy/nucleon ≈ 8.8 MeV at iron-56, making it most stable. Lighter nuclei release energy via fusion; heavier via fission. Memory tip: 'Iron peak: most stable nucleus; fusion before, fission after'. Nuclear physics concept frequently tested in competitive exams.

Explanation:
In uniform circular motion, speed is constant but velocity direction changes continuously, requiring centripetal acceleration directed toward the center (a = v²/r). By Newton's second law, a centripetal force must act. Velocity isn't constant (direction changes); acceleration isn't zero; force is required. Memory tip: 'Uniform circular motion: constant speed, changing velocity, center-seeking acceleration'. This conceptual question tests understanding of circular dynamics, crucial for mechanics in competitive exams. Always distinguish speed (scalar) from velocity (vector) in motion analysis.