question_answer

To determine the masses of the isotopes of an element which of the following techniques is useful [NCERT 1978; MNR 1979]

A)                 The acceleration of charged atoms by an electric field and their subsequent deflection by a variable magnetic field

B)                 The spectroscopic examination of the light emitted by vaporised elements subjected to electric discharge

C)                 The photographing of the diffraction patterns which arise when X-rays are passed through crystals

D)                 The bombardment of metal foil with alpha particles