Within elastic limit, which of the following graphs represents correctly the variation of extension in the  length of a wire with the external load?

A steel ring of radius r and cross = sectional area ‘A’ is fitted on to a wooden disc of radius R(R > r). If Young’s modulus be E, then the force with which the steel ring is expanded is

A light rod of length 2 m is suspended from the ceiling horizontally by means of two vertical wires of equal length tied to its end. One of the wires is made of steel and is of cross-section 0.1 cm². The other wire is of brass of cross-section 0.2 cm². A weight is suspended from a certain point of the rod such that equal stresses are produced in both the wires. Which of the following is correct?

A steel wire is suspended vertically from a rigid support. When loaded with a weight in air, it extends by la. When the weight is completely immersed in water, the extension is reduced to lw. Then the  relative density of the material of the weight is

A cylindrical vessel containing a liquid is closed by a smooth piston of mass m. If A is the cross-sectional area of the piston and P₀ is the atmospheric pressure, then the pressure of the liquid just below the piston is

What change in surface energy will be noted when a drop of radius R splits up into 1000 droplets, each of radius ‘r’ surface tension is T.

A number of droplets, each of radius r, combine to form a drop of radius R. If T is the surface tension, then the rise in temperature will be

A drop of water of volume V is pressed between the two glass plates so as to spread to an area A. If T is the surface tension, the normal force required to separate the glass plates is

Two spherical soap bubbles coalesce. If V is the consequent change in volume of the contained air, S is the total change in surface are and   is the surface tension of soap solution, then