The apparent weight of a person in an elevator moving downwards with an acceleration 'a' (where a < g) is: MCQ with Answer and Explanation

Explanation:
Pressure cooker seals steam, increasing internal pressure above atmospheric. Higher pressure raises water's boiling point (above 100°C), allowing food to cook at higher temperature, speeding up chemical reactions. Option A is vague; C and D are secondary effects. Memory tip: 'Higher pressure ⇒ higher boiling point ⇒ faster cooking'. This daily-life physics question tests application of pressure-temperature relationship in liquids, frequently appearing in competitive exams. Always recall that phase change temperatures depend on pressure (e.g., water boils below 100°C on mountains).

Explanation:
Refractive index n = c/v, where c = 3×10⁸ m/s (speed in vacuum). Thus v = c/n = (3×10⁸)/(4/3) = 3×10⁸ × 3/4 = 9/4 × 10⁸ = 2.25×10⁸ m/s. This direct formula application is fundamental in optics. Memory aid: 'Higher n ⇒ slower light in medium'. Competitive exams frequently test this calculation with common refractive indices (water 4/3, glass ~1.5). Always use c = 3×10⁸ m/s unless specified otherwise, and ensure unit consistency (m/s here).

Explanation:
Barometer measures atmospheric pressure. Mercury barometer (Torricelli) standard. Aneroid barometer. Manometer measures pressure difference. Hydrometer density. Lactometer milk purity.