A small hole of area of cross-section 2 mm² present near the bottom of a fully filled open tank of height 2 m. Taking g = 10 m/s², the rate of flow of water through the open hole would be nearly :

The unit of thermal conductivity is :

A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of 2.5 $$ \times $$ 10^–2 N/m. The pressure inside the bubble equals at a point Z₀ below the free surface of water in a container. Taking g = 10 m/s², density of water = 10³ kg/m³, the value of Z₀ is :

Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by $$\Delta $$l on applying a force F, how much force is needed to stretch the second wire by the same amount?