Myopia is corrected by MCQ with Answer and Explanation

Explanation:
Total time of flight T = 2u/g => u = gT/2 = 10×6/2 = 30 m/s. Max height H = u²/(2g) = 900/20 = 45 m. Alternatively, time to max height = 3 s, H = ½g t² = ½×10×9 = 45 m.

Explanation:
Thermostat uses differential expansion to make/break circuit.

Explanation:
Heat required Q = m c ΔT = 5 × 4200 × 20 = 420,000 J. Power 2000 W, time t = Q/P = 420000/2000 = 210 s.