The sap in trees, which consists aminly of water in summer, rises in a system of capilaries of radius `r = 2.5 xx 10^-5`m. The surface tension of sap is `T = 7.28 xx 10^-2 N m^-1` and the angle of contact is `0^@`. Does surface tension alone account for the supply of water to the top of all trees?

Two narrow bores of diameters 3.0 mm and 6.0 mm are joined together to form a U-tube open at both ends. If the U-tube contains water, what is the difference in its levels in the two limbs of the tube ? Surface tension of water at the temperature of the experiment is 7.3xx 10^-2 N m^-1 '. Take the angle of contact to be zero and density of water to be 1.0xx 10^3 kg m^- 3 ( g = 9.8 m s^-2 ) .

Two mercury droplets of radii 0.1 cm and 0.2 cm collapse into one single drop. What amount of energy is released ? The surface tension of mercury, T = 435.5 xx 10^-3 N m^-1

The rate of a first order reaction is : 1.5 xx 10^-2 mol L^-1 mi n^-1 at 0.5 M concentration of the reactant. The half life of the reaction is :

A point charge of 5 muC is situated at the centre of a sphere of radius 0.2 m. Calculate the electric flux through its surface. Given epsilon_0 = 8.854 xx 10^-12C^2N^-1m^-2

A wire stretched between two rigid supports vibrates in itsfundamental mode with a frequency of 45 Hz. The mass of the wire is 3.5 xx 10^-2 kg and itslinear mass density is 4.0 xx 10^-2 kg m^-1 . What is the tension in the string?

The refractive index of glass is 1.5 and that of water is 1.3.If the speed of light in water is 2.25 xx 10^8 m s^(-1) ,what is the speed of light in glass?

To what depth must a rubber ball be taken in deep sea so that its volume is decreased by 0.1%. (The bulk modulus of rubber is 9.8 xx 10^8 N m^-2 , and hte density of sea water is 10^3 k m^-3 ).

The tensile strength of steel is 5 xx 10^7 N m^-2 . Find the maximum length of the wire that can hang vertically , without breking it. Densityof steel is 8 xx 10^3 kg m^-3.

The radius of the innermost electron orbit of a hydrogen atom is 5.3 xx 10^-11 m . What are radii of the n=2 and n=3 orbits?