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?

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

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

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

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

455.

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

When the azimuthal quantum number has the value of 2, the number of orbitals possible are

• 7

• 5

• 0

• 3

The correct set of four quantum numbers for outermost electron of potassium (Z = 19) is

• 4, 1, 0, $\frac{1}{2}$

• 3, 1, 0, $\frac{1}{2}$

• 4, 0, 0, $\frac{1}{2}$

• 3, 0, 0, $\frac{1}{2}$

A body of mass x kg is moving with a velocity of 100 ms^-1. Its de-Broglie wavelength is 6.62 × 10^-35 m. Hence, x is (h = 6.62 × 10^-34 Js)

• 0.1 kg

• 0.25 kg

• 0.15 kg

• 0.2 kg

The wave number of the spectral line in the emission spectrum of hydrogen will be equal to $\frac{8}{9}$ times the rydberg's constant if the electron jumps from

• n =3 to n =1

• n = 10 to n=1

• n=9 to n=1

• n = 2 to n=1