A air bubble of radius 1 cm in water has an upward acceleration 9.8 cm s^–2. The density of water is 1 gm cm^–3 and water offers negligible drag force on the bubble. The mass of the bubble is (g = 980 cm/s²).

A metallic sphere cools from 50^oC to 40^o in 300 s. If atmospheric temperature around is 20^oC, then the sphere’s temperature after the next 5 minutes will be close to :

Pressure inside two soap bubbles are 1.01 and 1.02 atmosphere, respectively. The ratio of their volumes is :

A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm^–1, density = 667 kg m^–3) which rises to height h in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opp. sides of the capillary) make an angle of 60^o with one another. Then h is close to (g = 10 ms^–2)