The most massive subatomic particle is:

1. Proton
2. Neutron
3. Alpha particle
4. Beta particle

Subtopic:  Introduction of Atomic Structure |
From NCERT
Please attempt this question first.
Hints

Which of the following statements is/are not correct? 
(a) Isotones differ in the number of neutrons. 
(b) Isobars contain the same number of neutrons but differ in the number of protons.
(c) No isotope of hydrogen is radioactive.
(d) The density of the nucleus is much greater than that of an atom.
Choose the correct option:
1. (a), (b) and (c) 2. (b), (c) and (d)
3. (b) and (c) 4. All of the above.
Subtopic:  Number of Electron, Proton & Neutron |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

The angular momentum of an electron in an orbit of radius \(\mathrm{R}\) in a hydrogen atom is directly proportional to ____.
 
1. \(\mathrm{R}\) 2. \(\dfrac{1}{R}\)
3. \(\dfrac{1}{\sqrt{R}}\) 4. \(\sqrt{R}\)
Subtopic:  Bohr's Theory |
From NCERT
JEE
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

Which of the following statements are correct regarding orbits and orbitals?

(a) An orbit is a circular path where electrons revolve.
(b) An orbital is a 3D space with maximum electron probability (up to 90%).
(c) The maximum electrons in an orbit are 2n2.
(d) Orbitals are always circular in shape.
(e) Orbitals follow the wave nature of electrons and the uncertainty principle.

Options:

1. a, b, and c 2. b, c, and e
3. a, b,c and e 4. a, c, and d
Subtopic:  Bohr's Theory | Shell & Subshell |
 50%
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

Assertion (A): The mass numbers of most of the elements are fractional. 
Reason (R): Mass numbers are obtained by comparing with the mass number of carbon taken as \(12.\)

In light of the above statements choose the answer from the options given below:
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False 
4. Both (A) and (R) are False. 
Subtopic:  Number of Electron, Proton & Neutron |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

Hund’s rule states that:
 
1.  No two electrons can be in two separate orbitals.
2. No two electrons can be present with similar spin in an orbital.
3. Two electrons can exist in d orbital.
4. None of the above.
Subtopic:  Pauli's Exclusion Principle & Hund's Rule |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

What is the wavelength of light corresponding to photons with an energy of 1.00 × 103 kJ mol–1​​​​​​?

1. 2.00 × 1031 m
2. 1.20 × 10–7 m
3. 1.20 × 10–4 m
4. 8.36 × 106 m
Subtopic:  Photo Electric Effect |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

Given below are two statements: 
Statement I: The value of wave function, \(\Psi\) depends upon the coordinates of the electron in the atom. 
Statement II: The probability of finding an electron at a point within an atom is proportional to the orbital wave function. 
In light of the above statements, choose the correct answer from the options given below: 
1. Statement I is True but Statement II is False.
2. Statement I is False but Statement II is True.
3. Both Statement I and Statement II are True.
4. Both Statement I and Statement II are False.
Subtopic:  Quantum Numbers & Schrodinger Wave Equation |
From NCERT
NEET - 2023
To view explanation, please take trial in the course.
NEET 2026 - Target Batch - Vital
Hints
To view explanation, please take trial in the course.
NEET 2026 - Target Batch - Vital

A golf ball has a mass of 46 g and a speed of 45 m/s. If the speed can be measured within the accuracy of 3%, the uncertainty in the position is: 

1.  8.4×10-34m
2.  6.4×10-33m
3.  6.6×10-39m
4.  2.1×10-34m
Subtopic:  Heisenberg Uncertainty Principle |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

Match List I with List II 
List I (Frequency region) List II (Uses)
A. Radiofrequency I. Radar
B. Microwave II. Broadcast
C. Infra-red region III. Heating 
Choose the correct answer from the options given below:
 
A B C
1. II I III
2. I II III
3. I III II
4. II III I
Subtopic:  Electromagnetic Radiation |
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.