How to Score High in JEE Main 2025-26 Atoms and Nuclei Mock Tests
Atoms and Nuclei is a high-weightage chapter in JEE Physics, covering core topics like Bohr's atomic model, radioactivity, and nuclear reactions. This mock test will sharpen your concepts, boost problem-solving skills, and help you excel in JEE Main with in-depth practice on atom structure and nuclear physics. Attempt now to reinforce your preparation!
Mock Test Instructions for the Atoms And Nuclei Mock Test 2:
- 20 questions from Atoms And Nuclei Mock Test 2
- Time limit: 20 minutes
- Single correct answer per question
- Correct answers appear in bold green after submission
How Can JEE Mock Tests Help You Master Atoms and Nuclei?
- Identify strong and weak areas in Bohr’s model, radioactivity, and nuclear fission using timed practice questions.
- Track performance in atomic structure, nuclear reactions, and decay constants for targeted revision.
- Practice conceptual and calculation-based questions to excel in Atoms and Nuclei topics.
- Develop exam temperament and speed for solving JEE Main pattern questions from this chapter.
- Leverage mock test feedback to improve scores and confidence before the actual exam.
Excel at Atomic Structure and Nuclear Physics with Expert JEE Mock Tests
- Master PYQ patterns and JEE tricks on atom models and isotopes with chapter-wise online tests.
- Refine your understanding of electron transitions and nuclear energy levels through expert-designed MCQs.
- Boost your accuracy in questions on decay laws, mass number, binding energy, and more.
- Mock tests simulate real JEE Main timing and negative marking, building actual exam skills.
- Challenge yourself with a variety of MCQs, focusing on the most important concepts for scoring in Atoms and Nuclei.
Subject-Wise Excellence: JEE Main Mock Test Links
| S.No. | Subject-Specific JEE Main Online Mock Tests |
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| 1 | Online FREE Mock Test for JEE Main Chemistry |
| 2 | Online FREE Mock Test for JEE Main Maths |
| 3 | Online FREE Mock Test for JEE Main Physics |
Important Study Materials Links for JEE Exams
FAQs on Atoms and Nuclei JEE Main 2025-26 Mock Test: Practice & Solutions
1. What is an atom?
An atom is the smallest unit of matter retaining all properties of an element. It consists of a central nucleus made up of protons and neutrons, with electrons revolving around the nucleus in specific orbits. Atoms are the basic building blocks that compose all substances in the universe.
2. What is a nucleus in an atom?
The nucleus is the dense, central core of an atom, containing protons (positively charged particles) and neutrons (neutral particles). The nucleus holds almost all the mass of the atom and is surrounded by electrons in various energy levels.
3. What are isotopes?
Isotopes are atoms of the same element having the same number of protons but a different number of neutrons. This results in a different atomic mass but similar chemical properties. For example, hydrogen has three isotopes: protium, deuterium, and tritium.
4. What is radioactivity?
Radioactivity is a process by which an unstable atomic nucleus loses energy by emitting radiation such as alpha particles, beta particles, or gamma rays. This spontaneous disintegration helps unstable elements become more stable.
5. Name the types of radioactive decay.
The three main types of radioactive decay are:
1. Alpha decay: Emission of an alpha particle (4He nucleus)
2. Beta decay: Emission of either an electron (beta minus) or positron (beta plus)
3. Gamma decay: Emission of gamma rays (high-energy photons) with no change in mass or charge.
6. What is nuclear fission?
Nuclear fission is the process where a heavy nucleus (like uranium-235) splits into two or more lighter nuclei, accompanied by the release of a large amount of energy and neutrons. This process is used in nuclear reactors and atomic bombs.
7. What is nuclear fusion?
Nuclear fusion is the phenomenon where two light nuclei (such as hydrogen isotopes) combine under extremely high temperature and pressure to form a heavier nucleus, releasing enormous energy. Fusion is the process powering the sun and stars.
8. What is meant by half-life?
The half-life of a radioactive substance is the time required for half of the original nuclei in a sample to decay. Each isotope has a unique half-life, which helps in determining the age of rocks and fossils using radioactive dating.
9. Describe Bohr's model of the atom.
In Bohr's model of the atom, electrons revolve in fixed circular orbits around the nucleus at certain discrete distances. Each orbit has fixed energy, and electrons can jump between orbits by absorbing or emitting energy as photons. This model explains the stability and spectra of hydrogen-like atoms.
10. What are the differences between nuclear fission and nuclear fusion?
- Nuclear fission: Splitting of a heavy nucleus into lighter nuclei, releasing energy; occurs at lower temperatures; used in power plants.
- Nuclear fusion: Combining of light nuclei into a heavier nucleus, releasing larger amounts of energy; requires extremely high temperatures; occurs naturally in stars.
11. What are the applications of radioisotopes?
Radioisotopes have applications in various fields:
- Medical diagnosis and treatment (e.g., cancer therapy, imaging)
- Industrial usage (e.g., detecting leaks, measuring thickness)
- Agricultural research
- Archaeological dating (carbon dating)
12. Why are electrons not present inside the nucleus?
Electrons are not found inside the nucleus because their mass is much smaller and their de Broglie wavelength is too large to be confined within the extremely small volume of the nucleus. Instead, electrons move around the nucleus in various energy levels or shells.
