In an alpha particle scattering experiment distance of closest approach for the $\alpha$ particle is $4.5 \times 10^{-14} \mathrm{~m}$. If target nucleus has atomic number $80$ , then maximum velocity of $\alpha$-particle is . . . . .. $\times 10^5$ $\mathrm{m} / \mathrm{s}$ approximately.
$\left(\frac{1}{4 \pi \epsilon_0}=9 \times 10^9 \mathrm{SI}\right.$ unit, mass of $\alpha$ particle $=$ $\left.6.72 \times 10^{-27} \mathrm{~kg}\right)$
$155$
$156$
$157$
$158$
What does it mean if the $\alpha -$ particle passes through the foil of gold ?
In the Rutherford experiment, $\alpha -$ particles are scattered from a nucleus as shown. Out of the four paths, which path is not possible?
How many energy rays of $\alpha -$ particles emitted from $_{83}^{214}Bi$ were taken?
When the accelerating voltage applied on the electrons increased beyond a critical value
Which of the following statements are true regarding Bohr's model of hydrogen atom
$(I)$ Orbiting speed of electron decreases as it shifts to discrete orbits away from the nucleus
$(II)$ Radii of allowed orbits of electron are proportional to the principal quantum number
$(III)$ Frequency with which electrons orbits around the nucleus in discrete orbits is inversely proportional to the principal quantum number
$(IV)$ Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbitsSelect correct answer using the codes given belowCodes :