171.

The wavelength of associated wave of a particle moving with a speed of one-tenth that of light is 7Å. The particle must be

• electron

• proton

• nanoparticle

• photon

Which mathematical statement did not prove false?

• $∆\mathrm{E}= \mathrm{hv}$

• $\mathrm{R}=\frac{{\mathrm{me}}^4}{8{\mathrm{\epsilon }}_0^2{\mathrm{h}}^3\mathrm{c}}$

• $\mathrm{R}=\frac{{\mathrm{n}}_1^2{\mathrm{n}}_2^2\mathrm{v}}{({\mathrm{n}}_1^2-{\mathrm{n}}_2^2)\mathrm{c}}$

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

${}_{93}{}^{239}\mathrm{Np} \mathrm{is} \mathrm{a} \mathrm{\beta }- \mathrm{emitter}$, but the product is also radioactive and give ²³⁵U. Which particles(s) is/ are emitted by the product?

• 4 neutrons

• 4 protons

• 4 protons and 2electrons

• 2 neutrons and 2 protons

For a f-orbital, the values of m are

• -1, 0, +1

• 0, +1, +2, +3

• -2, -1, 0, +1, +2

• -3, -2, -1, 0, +1, +2, +3

A radio isotope will not emit

• gamma and alpha rays simultaneously

• gamma rays only

• alpha and beta rays simultaneously

• beta and gamma rays simultaneously

A lone pair of electrons in an atom implies

• a pair of valence electrons not involved in bonding

• a pair of electrons involved in bonding

• a pair of electrons

• a pair of valence electrons

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 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

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

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