Nuclei MCQs for NEET — Physics Questions with Answers

Statement I is false because nuclei of different atoms do not have the same size; their size depends on the mass number (A). Statement II is true because the radius of a nucleus is given by the formula $R = R_0(A)^{1/3}$, where $R_0$ is a constant and $A$ is the mass number. Hence, statement II is correct but does not support statement I.

$X (\eta ,\alpha)_3^7 Li $ $_Z^A{X}+_0{n}^1 -->_3^7{Li}+_2{He}^4$ By equating Z and A we get $_Z^A{X} -->_5^{10} {B}$

According to conservation of monentum $m_1v_1 + m_2 v_2 = 0$ $4v_1 + 206 v_2 = 0 $ $ 206 v_2 = - 4 v_2 $ $v_2 = {-4v_1 \over 206}$ Recoil speed of daughter nucleus is $4v \over 206$

$R = R_0 (3)^{1/3}$ , $R^1 = R_0 (81)^{1/3}$ ${R^1\over R} =({81\over 3 })^{1/3} = {(27)} ^ {1/3} =3 $ $ \therefore R^1 = 3R $

Isotones nucler have same neutrons i.e. A-Z are equal. From the given pairs $_{34} {se}^{74},_{31}{Ca}^{71}$ has same neutrons

Control rods in a nuclear reactor are made of materials that can absorb neutrons to control the rate of the nuclear reaction. Cadmium is a material that is highly effective at absorbing neutrons, which is why it is commonly used in control rods.

Uranium-235 ( $_{92}{U}^{235}$ ) is a naturally occurring isotope of uranium that is fissionable. This means it can sustain a nuclear chain reaction, which is the principle behind nuclear reactors and atomic bombs.

$_{92}U^{238} --->_{90}Th^{234}+ _{2}He^{4}$

$n-->p+e^- + \bar \upsilon$ $P-->n+e^-+\upsilon$