Atoms and Nuclei Test

Result

Atoms and Nuclei Test - 130

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

A mixture consists of two radioactive materials A₁ and A₂ with half lives of 20 s and 10 s respectively. Initially the mixture has 40 g of A₁ and 160 g of A₂. The amount of the two in the mixture will become equal after

A
60 s

B
80 s

C
20 s

D
40 s

Solution
Question 2
4 / -1

The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is

A
1/2

B
2/137

C
1/137

D
1/237

Solution
Question 3
4 / -1

In hydrogen atom, electron makes transition from n = 4 to n =1 level. Recoil momentum of the H atom will be

A
3.4 × 10^–27 N-s

B
6.8 × 10^–27 N-s

C
3.4 × 10^–24 N-s

D
6.8 × 10^–24 N-s

Solution
Question 4
4 / -1

A sodium atom is in one of the states labeled \'Lowest excited levels\'. It remains in that state for an average time of 10^–8 s, before to makes a transition back to a ground state. What is the uncertainty in energy of that excited state

A
6.56 × 10^–8 eV

B
2 × 10^–8 eV

C
10^–8 eV

D
8 × 10^–8 eV

Solution
Question 5
4 / -1

An energy of 24.6 eV is required to remove one of the electrons from a neutral helium atom. The energy (in eV) required to remove both the electrons from a neutral helium atom is

A
79.0

B
51.8

C
49.2

D
38.2

Solution
Question 6
4 / -1

A hydrogen atom in its ground state absorbs 10.2 eV of energy. The orbital angular momentum is increased by
(Given Planck\'s constant h = 6.6 × 10^–34 J - s

A
1.05 × 10^–34 J-s

B
3.16 × 10^–34 J-s

C
2.11 × 10^–34 J-s

D
4.22 × 10^–34 J-s

Solution
Question 7
4 / -1

Hydrogen (H), deuterium (D), singly ionized helium (He⁺) and doubly ionized lithium (Li⁺⁺) all have one electron around the nucleus. Consider n = 2 to n =1 transition. The wavelengths of emitted radiations are λ₁, λ₂, λ₃ and λ₄ respectively. Then approximately

A
λ₁ = λ₂ = 4λ₃ = 9λ₄

B
4λ₁ = 2λ₂ = 2λ₃ = λ₄

C
λ₁ =2λ₂= 2√2λ₃ =3√2λ₄

D
λ₁ = λ₂ = 2λ₃ = 3√2λ₄

Solution
Question 8
4 / -1

The number of revolutions per second made by an electron in the first Bohr orbit of hydrogen atom is of the order of

A
10²⁰

B
10¹⁹

C
10¹⁷

D
10¹⁵

Solution
Question 9
4 / -1

Consider an electron (m = 9.1 x 10^-31 kg) confined by electrical forces to move between rigid walls separated by 1.0 x 10^-9 metre, which is about five atomic diameters. The quantised energy value for the lowest stationary state is

A
12 x 1010^-20 J

B
6.0 x 10^-20 J

C
6.0 x 10^-18 J

D
6 J

Solution
Question 10
4 / -1

α–particles of energy 400 KeV are bombarded on nucleus of ₈₂Pb. In scattering of α–particles, its minimum distance from nucleus will be

A
0.59 nm

B
0.59 Å

C
5.9 pm

D
0.59 pm

Solution