Calculate the value of stress in a wire of steel having radius of 2mm, when 10kN of force is applied on it.

Calculate the resistivity of a wire having resistance .02 ohm, length = 10 m and area = 1mm^2

Calculate the depression in freezing point of water when 20g of CH_3CH_2CHClCOOH is added to 500g of water. (Given Ka=1.4xx10^(-3)K_f=1.86 )

Calculate the depression in the freezing point of water when 10 g of CH_3CH_2CHClCOOH is added to 250 g of water. K_a = 1.4xx10^-3 , K_f = 1.86 K kg mol^-1 .

A hockey ball of mass 200 g travelling at 10 m s^-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5m s^1 . Calculate the change of momentum occured in the motion of hockey ball by the force applied by the hockey stick.

A coil has an inductance of .2 henry. Calculate the value of induced emf when the current in the coil is changing at the rate of 150 ampere per sec.

The energies of the electron in the second and the third Bohr orbits of the hydrogen atoms are -5.42xx10^(19)J and -2.41xx10^(19)J respectively. Calculate the wavelength (in S.I. unit) of the emitted radiation, when the electron jumps from the third to the second orbit.

A 14.5 kg mass, fastened to the end of a steel wire of unstretched length 1.0 m, is whirled in a vertical circle with an angular velocity of 2 rev/s at the bottom of the circle. The cross-sectional area of the wire is 0.065 cm^2 . Calculate the elongation of the wire when the mass is at the lowest point of its path.

A wire of length L and radius r is fixed at one end and a force F applied to the other end produces an extension l. the extension produced in another wire of same material of length 2L and radius 2r by a force 2F is