MCQs of Atoms

Atoms MCQs

Showing 31 to 40 out of 146 Questions

31.

An electron in hydrogen atom makes a transition from fourth orbit to second orbit. What is the frequency of emitted radiation ? (where R = 10⁵ cm^-1)

(a)	$\frac{3}{4} \times 10^{15}$
(b)	$\frac{3}{16} \times 10^{15}$
(c)	$\frac{9}{16} \times 10^{15}$
(d)	$\frac{3}{8} \times 10^{15}$

32.

The order of energies of energy levels A, B and C is E_A < E_B < E_C. If wavelengths corresponding to transitions C → B, B → A and C → A are λ₁, λ₂ and λ₃ respectively, then which of the following relation is correct ?

(a)	λ₁+ λ₂ + λ₃ = 0
(b)	λ₃² = λ₁²+ λ₂²
(c)	$λ_{3} = \frac{λ_{1} λ_{2}}{λ_{1} + λ_{2}}$
(d)	λ₃ = λ₁+ λ₂

33.

The ratio of energies of electron in the first excited state to its second excited state in H-atom is _____

(a)	1 : 4
(b)	4 : 9
(c)	9 : 4
(d)	4 : 1

34.

For the first orbit of hydrogen atom the minimum excitation potential is _____ V. In ground state the energy of electron is 13.6 eV.

(a)	13.6
(b)	3.4
(c)	10.2
(d)	3.6

35.

An electron with energy 12.09 eV strikes a hydrogen atom in the ground state, and gives all its energy to the hydrogen atom. Therefore, hydrogen atom is excited to _____ state.

(a)	fourth
(b)	third
(c)	second
(d)	first

36.

The frequency of characteristic X-rays determines _____ property of target.

(a)	atomic weight
(b)	atomic number
(c)	melting point
(d)	conductivity

37.

Hydrogen atom will be in its ground state, if its electron is in _____

(a)	any energy level
(b)	the lowest energy state
(c)	the highest energy state
(d)	the intermediate state

38.

Which of the following parameters are the same for all hydrogen-like atoms and ions in their ground states ?

(a)	Radius of the orbit
(b)	Speed of the electron
(c)	Energy of the atom
(d)	Orbital angular momentum of the electron

39.

The negative energy of an electron in Bohr atom means it is _____

(a)	bound
(b)	in free state
(c)	unstable
(d)	None of above

40.

The number of lines present per unit length is known as _____

(a)	wavelength
(b)	wave number
(c)	Rydberg's constant
(d)	None of above

Showing 31 to 40 out of 146 Questions