{"id":6887,"date":"2026-10-05T10:26:32","date_gmt":"2026-10-05T10:26:32","guid":{"rendered":"https:\/\/ksquareinstitute.in\/blog\/?p=6887"},"modified":"2026-10-05T10:26:34","modified_gmt":"2026-10-05T10:26:34","slug":"modern-physics-neet-pyq-analysis","status":"publish","type":"post","link":"https:\/\/ksquareinstitute.in\/blog\/modern-physics-neet-pyq-analysis\/","title":{"rendered":"Modern Physics NEET PYQ Analysis: Dual Nature, Atoms and Nuclei"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Modern Physics is the most scoring unit in NEET Physics. Its three chapters, Dual Nature of Radiation and Matter, Atoms, and Nuclei, are short, formula-based and almost free of long calculations. This modern physics NEET PYQ analysis shows which question types NTA repeats and the shortcuts that solve them in seconds.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"432\" src=\"https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube-1024x432.jpg\" alt=\"Modern physics NEET PYQ analysis shown as light ejecting electrons from metal with an atom model behind\" class=\"wp-image-6888\" srcset=\"https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube-1024x432.jpg 1024w, https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube-300x127.jpg 300w, https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube-768x324.jpg 768w, https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube-1536x648.jpg 1536w, https:\/\/ksquareinstitute.in\/blog\/wp-content\/uploads\/2026\/10\/Modern-Physics-NEET-PYQ-Analysis-Photoelectric-Tube.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For concept building, pair this with our <a href=\"https:\/\/ksquareinstitute.in\/blog\/modern-physics-for-neet-2027\">modern physics preparation guide<\/a>, and see the bigger picture in our <a href=\"https:\/\/ksquareinstitute.in\/blog\/neet-2027-physics-preparation\">complete NEET Physics strategy<\/a>. This article focuses on what past papers actually ask.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Want to test yourself first? Solve the free <a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/dual-nature-of-radiation-and-matter\/questions\/\" target=\"_blank\" rel=\"noopener\">Dual Nature of Radiation and Matter PYQs<\/a>, <a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/atoms\/questions\/\" target=\"_blank\" rel=\"noopener\">Atoms PYQs<\/a> and <a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/nuclei\/questions\/\" target=\"_blank\" rel=\"noopener\">Nuclei PYQs<\/a>, then use this guide to fix the gaps.<\/p>\n\n\n\n<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><h2>Table of Contents<\/h2><nav><ul><li><a href=\"#why-modern-physics-is-the-best-return-on-time\">Why Modern Physics Is the Best Return on Time<\/a><\/li><li><a href=\"#modern-physics-neet-pyq-analysis-the-repeated-question-types\">Modern Physics NEET PYQ Analysis: The Repeated Question Types<\/a><\/li><li><a href=\"#photoelectric-effect\">Photoelectric Effect<\/a><\/li><li><a href=\"#de-broglie-wavelength\">de Broglie Wavelength<\/a><\/li><li><a href=\"#bohr-model-of-hydrogen\">Bohr Model of Hydrogen<\/a><\/li><li><a href=\"#nuclei-size-mass-defect-and-binding-energy\">Nuclei: Size, Mass Defect and Binding Energy<\/a><\/li><li><a href=\"#worked-pyq-pattern-questions\">Worked PYQ-Pattern Questions<\/a><\/li><li><a href=\"#common-traps-to-avoid\">Common Traps to Avoid<\/a><\/li><li><a href=\"#practise-every-modern-physics-pyq\">Practise Every Modern Physics PYQ<\/a><\/li><li><a href=\"#conclusion\">Conclusion<\/a><\/li><li><a href=\"#\u2753-faq\">FAQ<\/a><\/li><\/ul><\/nav><\/div>\n\n\n\n<h2 id=\"why-modern-physics-is-the-best-return-on-time\" class=\"wp-block-heading\">Why Modern Physics Is the Best Return on Time<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">NEET usually asks four to five questions from these three chapters together. The theory fits in about 40 NCERT pages, so no other Physics unit gives as many marks for so little reading.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Keep the class notes open while you revise: <a href=\"https:\/\/ksquareinstitute.in\/blog\/dual-nature-of-radiation-and-matter-class-12\">Dual Nature class 12 notes<\/a>, <a href=\"https:\/\/ksquareinstitute.in\/blog\/atoms-class-12-notes\">Atoms class 12 notes<\/a> and <a href=\"https:\/\/ksquareinstitute.in\/blog\/nuclei-class-12-notes\">Nuclei class 12 notes<\/a>.<\/p>\n\n\n\n<h2 id=\"modern-physics-neet-pyq-analysis-the-repeated-question-types\" class=\"wp-block-heading\">Modern Physics NEET PYQ Analysis: The Repeated Question Types<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">After sorting a decade of NEET physics PYQs from these three chapters, the questions fall into six families.<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-white-background-color has-background has-border-color has-black-border-color\" style=\"border-width:2px\"><thead><tr><th>Question family<\/th><th class=\"has-text-align-center\" data-align=\"center\">Frequency<\/th><th>What it tests<\/th><\/tr><\/thead><tbody><tr><td>Photoelectric effect<\/td><td class=\"has-text-align-center\" data-align=\"center\">Most frequent<\/td><td>Einstein&#8217;s equation, stopping potential, graphs<\/td><\/tr><tr><td>de Broglie wavelength<\/td><td class=\"has-text-align-center\" data-align=\"center\">Very frequent<\/td><td>Dependence on momentum, energy and voltage<\/td><\/tr><tr><td>Bohr model of hydrogen<\/td><td class=\"has-text-align-center\" data-align=\"center\">Very frequent<\/td><td>Radius, energy and speed in the nth orbit<\/td><\/tr><tr><td>Spectral series<\/td><td class=\"has-text-align-center\" data-align=\"center\">Regular<\/td><td>Series, region, number of lines<\/td><\/tr><tr><td>Binding energy<\/td><td class=\"has-text-align-center\" data-align=\"center\">Very frequent<\/td><td>Mass defect, energy released, stability<\/td><\/tr><tr><td>Nuclear size and density<\/td><td class=\"has-text-align-center\" data-align=\"center\">Regular<\/td><td>R = R\u2080A^(1\/3), constant density<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For a quick warm-up before the full set, try these <a href=\"https:\/\/ksquareinstitute.in\/blog\/physics-modern-physics-pyqs\">modern physics warm-up questions<\/a>.<\/p>\n\n\n\n<h2 id=\"photoelectric-effect\" class=\"wp-block-heading\">Photoelectric Effect<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Einstein&#8217;s equation: <strong>K_max = h\u03bd \u2212 \u03c6<\/strong>, where \u03c6 is the work function.<\/li>\n\n\n\n<li>Stopping potential: eV\u2080 = K_max.<\/li>\n\n\n\n<li>Threshold frequency: \u03bd\u2080 = \u03c6\/h. Below it, no electrons are emitted, whatever the intensity.<\/li>\n\n\n\n<li>Shortcut: E (in eV) = 1240\/\u03bb (in nm).<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">What depends on what:<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-white-background-color has-background has-border-color has-black-border-color\" style=\"border-width:2px\"><thead><tr><th>Change<\/th><th>Effect<\/th><\/tr><\/thead><tbody><tr><td>Intensity increased (same frequency)<\/td><td>Photocurrent increases; K_max and stopping potential unchanged<\/td><\/tr><tr><td>Frequency increased (same intensity)<\/td><td>K_max and stopping potential increase<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">In the graph of stopping potential against frequency, the slope is h\/e for every metal. Only the intercept changes with the metal. Photoelectric effect questions are usually built on this table or this graph.<\/p>\n\n\n\n<h2 id=\"de-broglie-wavelength\" class=\"wp-block-heading\">de Broglie Wavelength<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u03bb = h\/p = h\/mv<\/li>\n\n\n\n<li>In terms of kinetic energy: \u03bb = h\/\u221a(2mK)<\/li>\n\n\n\n<li>For a charge q accelerated through V: \u03bb = h\/\u221a(2mqV)<\/li>\n\n\n\n<li>For an electron: \u03bb = 12.27\/\u221aV \u00c5<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">So the de Broglie wavelength falls as momentum rises. For the same kinetic energy, the heavier particle has the shorter wavelength. For the same momentum, all particles have the same wavelength.<\/p>\n\n\n\n<h2 id=\"bohr-model-of-hydrogen\" class=\"wp-block-heading\">Bohr Model of Hydrogen<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For a hydrogen-like atom of atomic number Z, in the nth orbit:<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-white-background-color has-background has-border-color has-black-border-color\" style=\"border-width:2px\"><thead><tr><th>Quantity<\/th><th class=\"has-text-align-center\" data-align=\"center\">Formula<\/th><th class=\"has-text-align-center\" data-align=\"center\">Depends on<\/th><\/tr><\/thead><tbody><tr><td>Radius<\/td><td class=\"has-text-align-center\" data-align=\"center\">0.529 n\u00b2\/Z \u00c5<\/td><td class=\"has-text-align-center\" data-align=\"center\">n\u00b2\/Z<\/td><\/tr><tr><td>Energy<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u221213.6 Z\u00b2\/n\u00b2 eV<\/td><td class=\"has-text-align-center\" data-align=\"center\">Z\u00b2\/n\u00b2<\/td><\/tr><tr><td>Speed<\/td><td class=\"has-text-align-center\" data-align=\"center\">2.18 \u00d7 10\u2076 Z\/n m\/s<\/td><td class=\"has-text-align-center\" data-align=\"center\">Z\/n<\/td><\/tr><tr><td>Angular momentum<\/td><td class=\"has-text-align-center\" data-align=\"center\">nh\/2\u03c0<\/td><td class=\"has-text-align-center\" data-align=\"center\">n<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Kinetic energy = \u2212(total energy); potential energy = 2 \u00d7 (total energy).<\/li>\n\n\n\n<li>Ionisation energy of hydrogen from the ground state is 13.6 eV.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Spectral series:<\/strong> Lyman (to n = 1, ultraviolet), Balmer (to n = 2, visible), Paschen (to n = 3, infrared). The number of spectral lines from the nth level is n(n \u2212 1)\/2.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The Bohr model applies only to single-electron species such as H, He\u207a and Li\u00b2\u207a.<\/p>\n\n\n\n<h2 id=\"nuclei-size-mass-defect-and-binding-energy\" class=\"wp-block-heading\">Nuclei: Size, Mass Defect and Binding Energy<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Radius: R = R\u2080A^(1\/3), with R\u2080 \u2248 1.2 fm.<\/li>\n\n\n\n<li>Nuclear density is about 2.3 \u00d7 10\u00b9\u2077 kg\/m\u00b3 and is the same for all nuclei.<\/li>\n\n\n\n<li>Mass defect: \u0394m = [Zm_p + (A \u2212 Z)m_n] \u2212 M.<\/li>\n\n\n\n<li>Binding energy = \u0394m \u00d7 c\u00b2, and 1 u = 931.5 MeV.<\/li>\n\n\n\n<li>Binding energy per nucleon is highest (about 8.75 MeV) near iron-56, so medium nuclei are the most stable.<\/li>\n\n\n\n<li>Heavy nuclei release energy by <strong>fission<\/strong>; light nuclei release energy by <strong>fusion<\/strong>.<\/li>\n\n\n\n<li>Energy released in a reaction: Q = (binding energy of products) \u2212 (binding energy of reactants).<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The current syllabus for Nuclei centres on nuclear size, mass-energy, binding energy, fission and fusion. Check the official syllabus before spending time on the radioactive decay law.<\/p>\n\n\n\n<h2 id=\"worked-pyq-pattern-questions\" class=\"wp-block-heading\">Worked PYQ-Pattern Questions<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q1. Light of photon energy 4 eV falls on a metal of work function 2.5 eV. What is the stopping potential?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Answer: 1.5 V.<\/strong> K_max = 4 \u2212 2.5 = 1.5 eV, so V\u2080 = 1.5 V.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q2. The intensity of light is doubled at the same frequency. What happens to K_max and the photocurrent?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Answer: K_max is unchanged; the photocurrent doubles.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q3. An electron in hydrogen jumps from n = 3 to n = 1. What is the energy of the photon emitted?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Answer: 12.09 eV.<\/strong> E = 13.6 (1 \u2212 1\/9) = 12.09 eV.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q4. What is the ratio of the radii of nuclei with mass numbers 27 and 64?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Answer: 3 : 4.<\/strong> R \u221d A^(1\/3), and the cube roots are 3 and 4.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q5. The kinetic energy of a particle becomes four times. How does its de Broglie wavelength change?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Answer: It is halved.<\/strong> \u03bb \u221d 1\/\u221aK.<\/p>\n\n\n\n<h2 id=\"common-traps-to-avoid\" class=\"wp-block-heading\">Common Traps to Avoid<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Saying K_max increases with intensity<\/li>\n\n\n\n<li>Using the electron formula 12.27\/\u221aV for a proton<\/li>\n\n\n\n<li>Mixing up the n-dependence of radius, energy and speed<\/li>\n\n\n\n<li>Forgetting that total energy in a Bohr orbit is negative<\/li>\n\n\n\n<li>Assuming a heavier nucleus is denser<\/li>\n<\/ul>\n\n\n\n<h2 id=\"practise-every-modern-physics-pyq\" class=\"wp-block-heading\">Practise Every Modern Physics PYQ<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The fastest way to lock in these patterns is to solve real past questions, chapter by chapter. All three chapters are available chapter-wise, free:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udc49 <strong><a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/dual-nature-of-radiation-and-matter\/\" target=\"_blank\" rel=\"noopener\">Solve Dual Nature of Radiation and Matter NEET PYQs<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udc49 <strong><a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/atoms\/\" target=\"_blank\" rel=\"noopener\">Solve Atoms NEET PYQs<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udc49 <strong><a href=\"https:\/\/ksquareinstitute.com\/questions\/neet-previous-year-questions\/physics\/nuclei\/\" target=\"_blank\" rel=\"noopener\">Solve Nuclei NEET PYQs<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">One chapter a day is enough. In three days, the whole unit is done.<\/p>\n\n\n\n<h2 id=\"conclusion\" class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This unit is short, predictable and generous. Use this modern physics NEET PYQ analysis to master the photoelectric equation, the wavelength relations, the Bohr formulas and binding energy. Then practise until each question takes under a minute.<\/p>\n\n\n\n<h2 id=\"\u2753-faq\" class=\"wp-block-heading\">\u2753 FAQ<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: How many questions come from Modern Physics in NEET?<\/strong> A: Usually four to five questions from Dual Nature, Atoms and Nuclei together, which is up to 20 marks.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: Which chapter of Modern Physics is most important?<\/strong> A: Dual Nature of Radiation and Matter gives the most questions, mainly on the photoelectric effect and matter waves. Atoms and Nuclei follow closely.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: Is Modern Physics easy for NEET?<\/strong> A: Yes. The chapters are short and the questions are mostly direct formula applications, so it is one of the most scoring units.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: Does stopping potential depend on intensity?<\/strong> A: No. Stopping potential depends on the frequency of light and the work function of the metal, not on intensity.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: How should I revise this unit?<\/strong> A: Use a modern physics NEET PYQ analysis to list the repeated question types, make a one-page formula sheet, and solve past questions chapter-wise.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q: Where can I practise Modern Physics NEET PYQs for free?<\/strong> A: You can solve every previous year question from all three chapters for free using the practice links in this article.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Modern Physics is the most scoring unit in NEET Physics. Its three chapters, Dual Nature of Radiation and Matter, Atoms, and Nuclei, are short, formula-based and almost free of long calculations. This modern physics NEET PYQ analysis shows which question types NTA repeats and the shortcuts that solve them in seconds. For concept building, pair [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":6888,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,2,70],"tags":[4176,3227,3225,602,3228,4178,4179,7,13,2328,4177,3221,4007],"class_list":["post-6887","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-study-tips","category-neet","category-physics","tag-atoms","tag-binding-energy","tag-bohr-model","tag-class-12-physics","tag-de-broglie-wavelength","tag-dual-nature-of-radiation-and-matter","tag-modern-physics","tag-neet-2027","tag-neet-physics","tag-neet-pyq","tag-nuclei","tag-photoelectric-effect","tag-previous-year-questions"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":8}},"_links":{"self":[{"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/posts\/6887","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/comments?post=6887"}],"version-history":[{"count":1,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/posts\/6887\/revisions"}],"predecessor-version":[{"id":6889,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/posts\/6887\/revisions\/6889"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/media\/6888"}],"wp:attachment":[{"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/media?parent=6887"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/categories?post=6887"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ksquareinstitute.in\/blog\/wp-json\/wp\/v2\/tags?post=6887"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}