An artificial radioactive isotope gave ${}_7^{14}$N after two successive β-particle emissions. The number of neutrons in the parent nucleus must be

• 9

• 14

• 5

• 7

Nuclear theory of the atom was put forward by

• Rutherford

• Aston

• Neils Bohr

• J.J. Thomson

The number of 2p electrons having spin quantum number s =-1/2 are

• 6

• 0

• 2

• 3

194.

The number of α and β- particles emitted during the transformation of ₉₀Th²³² to ₈₂Pb²⁰⁸ respectively are

• 4, 2

• 2, 2

• 8, 6

• 6, 4

Angular momentum ofan electron in the n^th orbit of hydrogen atom is given by

• $\frac{\mathrm{nh}}{2\mathrm{\pi }}$

• nh

• $\frac{2\mathrm{\pi }}{\mathrm{nh}}$

• $\frac{\mathrm{\pi }}{2\mathrm{nh}}$

The rate at which a substance reacts depends on its

• atomic weight

• atomic number

• molecular weight

• active mass

Which of the following cannot be accelerated?

• α-particle

• β-particle

• protons

• neutrons

In which of the following nuclear reaction neutrons is emitted?

• ${}_{13}{}^{27}\mathrm{Al} + {}_2{}^4\mathrm{He} \to {}_{15}{}^{30}\mathrm{P}$

• ${}_6{}^{12}\mathrm{C} + {}_1{}^1\mathrm{H} \to {}_7{}^{13}\mathrm{N}$

• ${}_{15}{}^{30}\mathrm{P} \to {}_{14}{}^{30}\mathrm{Si}$

• ${}_{96}{}^{241}\mathrm{Am} + {}_2{}^4\mathrm{He} \to {}_{97}{}^{245}\mathrm{Bk}$

Formation of coloured solution is possible when metal ion in the compound contains

• paired electrons

• lone pair of electrons

• unpaired electrons

• none of the above

A body of mass 10 mg is moving with a velocity of 100 ms^-1. The wavelength of de-Broglie wave associated with it would be (h = 6.63 × 10^-34 Js)

• 6.63 × 10^-35 m

• 6.63 × 10^-34 m

• 6.63 × 10^-31 m

• 6.63 × 10^-37 m