An $\alpha$-particle of energy $4\ MeV$ is scattered through $180^o $ by a fixed uranium nucleus. The distance of the closest approach is of the order of
$1\ Å$
${10^{ - 10}}\ cm$
${10^{ - 12}}\ cm$
${10^{ - 15}}\ cm$
An electron having de-Broglie wavelength $\lambda$ is incident on a target in a X-ray tube. Cut-off wavelength of emitted $X$-ray is :
In 1911 , the physicist Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property which led Rutherford to use gold was that it was
What is plum pudding model of the atom ?
Orbital acceleration of electron is
Which one of the relation is correct between time period and number of orbits while an electron is revolving in a orbit