The phenomenon of beats is used in: MCQ with Answer and Explanation

Explanation:
Myopia (nearsightedness) is the inability to see distant objects clearly, with far point less than infinity. Here, far point is 2 m. Corrected using concave lens. Hypermetropia (farsightedness) affects near vision; presbyopia is age-related loss of accommodation; astigmatism involves uneven corneal curvature. Memory aid: 'Myopia = near-sighted; far point reduced'. This application question tests knowledge of vision defects and corrections, frequently appearing in competitive exams. Always link symptom (blurred distant vision) to defect (myopia) and correction (diverging lens).

Explanation:
Submerged fraction = ρ_ice/ρ_water = 0.9, above = 0.1 (10%).

Explanation:
Resonance (amplification at natural frequency) is exploited in musical instruments (e.g., guitar body resonates with string frequencies) and tuning forks (designed to vibrate at precise frequency for calibration). Memory tip: 'Resonance applications: musical instruments (amplify sound), tuning forks (frequency standard), bridges (avoid resonance to prevent collapse)'. This application question tests wave phenomena uses, frequently appearing in competitive exams. Always link physical principles to practical applications; competitive exams emphasize real-world relevance of physics concepts, including both beneficial and hazardous aspects of resonance.