MCQs of Atoms

Atoms MCQs

Showing 101 to 110 out of 146 Questions

101.

An electron in H-atom makes a transition from n = 3 to n = 1. The recoil momentum of H-atom will be _____.

(a)	6.45 × 10^-27 Ns
(b)	6.8 × 10^-27 Ns
(c)	6.45 × 10^-24 Ns
(d)	6.8 × 10^-24 Ns

102.

The acceleration of electron in the first orbit of hydrogen atom is _____.

(a)	$\frac{4 π^{2} m}{h^{3}}$
(b)	$\frac{h^{2}}{4 π^{2} m r}$
(c)	$\frac{h^{2}}{4 π^{2} m^{2} r^{3}}$
(d)	$\frac{m^{2} h^{2}}{4 π^{2} r^{3}}$

103.

The speed of electron in the second orbit of Be³⁺ ion will be _____ .

(a)	$\frac{c}{137}$
(b)	$\frac{2 c}{137}$
(c)	$\frac{3 c}{137}$
(d)	$\frac{4 c}{137}$

104.

The total energy of electron is the ground state of the hydrogen atom is -13.6 eV. The potential energy of an electron in the ground state of Li⁺² ion will be _____.

(a)	122.4 eV
(b)	-122.4 eV
(c)	244.8 eV
(d)	-244.8 eV

105.

The force acting on the electron in a hydrogen atom depends on the principal quantum number as _____.

(a)	$F \propto n^{2}$
(b)	$F \propto \frac{1}{n^{2}}$
(c)	$F \propto n^{4}$
(d)	$F \propto \frac{1}{n^{4}}$

106.

The average life time of an excited state of hydrogen atom is 10^-8. An electron is revolving in the second orbit of 1.1 × 10⁶ m/s. What is the frequency of the electron in this orbit ?

(a)	2.4 × 10¹⁴Hz
(b)	6.18 × 10¹⁴Hz
(c)	8.2 × 10¹⁴Hz
(d)	None of the above

107.

The difference between the longest wavelength line of the Balmer series and Shortest wavelength line of the Lyman series for a Hydrogen atom(atomic number Z) equals to Δλ. The value of the Rydberg constant for the given atom is _____ .

(a)	$\frac{5}{31} \frac{1}{∆ λ \cdot Z^{2}}$
(b)	$\frac{5}{36} \frac{Z^{2}}{∆ λ}$
(c)	$\frac{31}{5} \frac{1}{∆ λ \cdot Z^{2}}$
(d)	None of the above

108.

In the Bohr model of the atom, if a, b and c are the radius, speed and energy of the electron in n th orbit, we have _____ .

(a)	ab ∝ n
(b)	ac ∝ n
(c)	bc ∝ n
(d)	$\frac{a}{c} \propto n$

109.

An electron in a hydrogen atom makes a transition from n = n₁ to n = n₂. The time period of the electron in the initial state is eight times that in the final state. The possible values of n₁ and n₂ are _____.

(a)	n₁ = 4,n₂ = 2
(b)	n₁ = 8,n₂ = 2
(c)	n₁ = 4,n₂ = 1
(d)	n₁ = 6,n₂ = 6

110.

The angular momentum of an electron in hydrogen atom is

\frac{4 h}{2 π}

. Kinetic energy of this electron is _____.

(a)	4.35 eV
(b)	1.51 eV
(c)	0.85 eV
(d)	13.6 eV

Showing 101 to 110 out of 146 Questions