491.

Splitting of spectrum lines in magnetic field is

• Stark effect

• Raman effect

• Zeeman effect

• Rutherford effect

Decrease in atomic number is not observed during

• β- emission

• α- emission

• positron emission

• electron capture

According to Bohr's theory, the angular momentum for an electron in 5^th orbit is

• 2.5 h/ $\mathrm{\pi }$

• 5 h/ $\mathrm{\pi }$

• 25 h/ $\mathrm{\pi }$

• 5 $\mathrm{\pi }$/ 2h

If a species has 16 protons, 18 electrons and 16 neutrons, the symbol (with charge) of species is

• S^-

• Si^2-

• P^3-

• S^2-

'No two electrons in an atom can have the same set of  quantum numbers.' This principle is known by which one of the following?

• Zeeman's exclusion principle

• Stark's exclusion principle

• Pauli's exclusion principle

• Hersbach's exclusion principle

Consider the ground state of Cr atom (Z= 24). The numbers of electrons with the azimuthal quantum numbers, l = 1 and 2 are respectively

• 12 and 4

• 12 and 5

• 16 and 4

• 16 and 5

What is the wavelength associated with a tennis ball of mass 10³ g and travelling at a velocity of 6.626 ms^-1 ?[h = 6.626 x 10^-34 Js^-1].

• 10^-34 m

• 10^-31 m

• 6.626 m

• 6.626 × 10^-31 m

What is the energy required to move the electron from ground state of H atom to the first excited state? Given that the ground state energy of H atom is 13.6 eV and that the energy E_n of an electron in nth orbital of an atom or ion of atomic number Z is given by the equation En= - (13.6Z² /n²).

• 13.6 eV

• 3.4 eV

• 10.2 eV

• -10.2 eV

Which electron orbitals are designated by
(i) n = 2, l = 1, m = 0;
(ii) n = 3, l=2, m = O;
(iii) n=4, l = 2, m=1 and
(iv) n = 5, l=3, m=3 respectively?

• 2p, 3d, 4d and 5f, respectively

• 2p, 3d, 4d and 5d, respectively

• 2p, 3d, 4f and 5f, respectively

• 2p, 3p, 4d and 5f, respectively

Which one of the following represents the correct ratio of the energy of electron in ground state of H atom to that of the electron in the first excited state of Li⁺?

• 4 : 9

• 9 : 4

• 1 : 4

• 4 : 1