A leak proof cylinder of length $1\mathrm{m}$ $$ , made of a metal which has very low coefficient of expansion is floating vertically in water at $0^{?}\mathrm{C}$ ${}^{}$ such that its height above the water surface is $20\mathrm{c}\mathrm{m}$ $$ . When the temperature of water is increased to $4^{?}\mathrm{C}$ ${}^{}$ , the height of the cylinder above the water surface becomes $$ $21\mathrm{c}\mathrm{m}$ . The density of water at $\mathrm{T}=4^{?}\mathrm{C}$ ${}^{}$ , relative to the density at $\mathrm{T}=0^{?}\mathrm{C}$ ${}^{}$ is close to:

Two SHMs in same direction are represented by y1 = asinωt and y2 = asin(ωt + δ). When they superimpose, the initial phase difference of the resultant SHM is

The potential energy of a particle of mass 2 kg in motion along the x-axis is given by U = 2 (1 – cos 2x) J, where x is in meters. The period of small oscillations (in s) is

A child is standing with folded hands at the centre of a platform rotating about its central axis. The kinetic energy of the system is K. The child now stretches his arms so that the moment of inertia of the system becomes 3/2 of the initial moment of inertia. The kinetic energy of the system is now

If the absolute temperature of hot black body is raised by 2%, by how much percentage rate of heat energy radiated would be increased nearly?

Two moles of helium gas are taken over the cycle ABCDA as shown below in P-T diagram. Assuming the gas to be ideal, the work done on the gas in taking from A to B is