X-rays of wavelength 1.54 A ∘ strike a crystal and are observed to be deflected at a angle of '22.5overset(@)' . Assuming that n=1, calculate the spacing between the planes of atoms that are responsible for this reflection.

A ball moving with momentum of 5kgms^-1 strikes against a wall at an angle 45^@ and is reflected at the same angle. Calculate the change in momentum.

(Attempt any nine of the following questions) There is an electric dipole on the x-y plane. Its dipole moment is 4 x 10^(-9) Cm . On . the same plane there is also a uniform electric field of magnitude 5x10^4 NC^(-1) . If the axis of the dipole makes an angle 30° with the electric field, calculate the magnitude of the torque acting on the dipole and also mention the di rection of torque.