META DESCRIPTIONPractise for NEET 2027 with 38 subject-wise questions on Atoms, Some Basic Concepts of Chemistry, and Organisms and Populations. Includes MCQs, numerical problems, assertion–reason questions, answer keys, explanations and revision formulas.KEYWORDSNEET 2027, NEET 2027 practice questions, Atoms MCQs, Bohr model questions, Mole Concept, Limiting Reagent, Organisms and Populations, NEET Biology MCQs, NCERT practice, NEET numerical questions.HASHTAGS#NEET2027 #NEETPreparation #NEETPractice #Physics #Atoms #Chemistry #MoleConcept #Biology #OrganismsAndPopulations #NCERT #NEETQuestions
NEET 2027 Possible Questions — Part 90
Advanced Subject-Wise Practice Set
Target Examination: NEET UG 2027
Level: NEET-oriented | Conceptual | Numerical | Exam Simulation
Topics Covered
Physics: Atoms
Chemistry: Some Basic Concepts of Chemistry
Biology: Organisms and Populations
Total Questions: 38
Suggested Time: 45–50 minutes
Important Note: This is an independently prepared practice set for educational purposes. These are not official NTA questions, and no question is guaranteed to appear in NEET 2027.
SECTION A: PHYSICS
Topic: Atoms
Multiple-Choice Questions
Q1. According to Bohr's model, the angular momentum of an electron in an allowed orbit is:
A. nh
B. \dfrac{nh}{2\pi}
C. \dfrac{h}{n}
D. \dfrac{2\pi h}{n}
Q2. The radius of the first Bohr orbit of a hydrogen atom is approximately:
A. 0.529\ \text{Å}
B. 5.29\ \text{Å}
C. 0.0529\ \text{Å}
D. 52.9\ \text{Å}
Q3. The energy of an electron in the ground state of a hydrogen atom is:
A. +13.6\ \text{eV}
B. -3.4\ \text{eV}
C. -13.6\ \text{eV}
D. 0\ \text{eV}
Q4. When an electron in a hydrogen atom moves from n=3 to n=2, the atom:
A. Absorbs a photon
B. Emits a photon
C. Loses its nucleus
D. Remains at the same energy
Q5. The ionisation energy of a hydrogen atom in its ground state is:
A. 3.4\ \text{eV}
B. 10.2\ \text{eV}
C. 13.6\ \text{eV}
D. 27.2\ \text{eV}
Q6. The spectral series of hydrogen corresponding to transitions ending at n=1 is called:
A. Balmer series
B. Paschen series
C. Brackett series
D. Lyman series
Q7. The energy of an electron in the nth orbit of hydrogen is proportional to:
A. n^2
B. 1/n
C. 1/n^2
D. n
Q8. Which transition in a hydrogen atom produces the photon with the greatest energy?
A. n=4\rightarrow n=3
B. n=3\rightarrow n=2
C. n=2\rightarrow n=1
D. n=5\rightarrow n=4
Numerical Questions
Q9. Calculate the energy of an electron in the second energy level of a hydrogen atom.
Use:
[ E_n=\frac{-13.6}{n^2}\ \text{eV} ]
Q10. Calculate the energy of the photon emitted when an electron in a hydrogen atom transitions from n=3 to n=2.
Use:
[ E_n=\frac{-13.6}{n^2}\ \text{eV} ]
Q11. Assertion–Reason
Assertion (A): The energy of an electron in a hydrogen atom is negative in its bound states.
Reason (R): The zero of energy is conventionally taken when the electron and proton are infinitely separated.
Choose the correct answer:
A. Both A and R are true, and R correctly explains A.
B. Both A and R are true, but R does not correctly explain A.
C. A is true, but R is false.
D. A is false, but R is true.
Q12. Which statement about the hydrogen emission spectrum is correct?
A. The spectrum is continuous at all wavelengths.
B. Electrons can have any arbitrary energy in the Bohr model.
C. Spectral lines arise from transitions between allowed energy levels.
D. Every transition emits a photon of identical energy.
Physics Formula Revision
Bohr's angular momentum quantisation:
[ mvr=\frac{nh}{2\pi} ]
Radius of the hydrogen atom's nth orbit:
[ r_n=a_0n^2 ]
Energy of the nth level:
[ E_n=\frac{-13.6}{n^2}\ \text{eV} ]
Photon energy during a transition:
[ E_\gamma=|E_f-E_i| ]
Rydberg equation:
[ \frac{1}{\lambda} =R_H\left(\frac{1}{n_f^2}-\frac{1}{n_i^2}\right) ]
For emission, n_i>n_f.
SECTION B: CHEMISTRY
Topic: Some Basic Concepts of Chemistry
Multiple-Choice Questions
Q13. The number of particles present in one mole of a substance is approximately:
A. 6.022\times10^{20}
B. 6.022\times10^{23}
C. 3.011\times10^{23}
D. 1.000\times10^{23}
Q14. The molar mass of carbon dioxide (CO_2) is:
A. 28\ \text{g mol}^{-1}
B. 32\ \text{g mol}^{-1}
C. 40\ \text{g mol}^{-1}
D. 44\ \text{g mol}^{-1}
Q15. How many moles are present in 18 g of water?
Given molar mass of water = 18\ \text{g mol}^{-1}.
A. 0.5 mol
B. 1 mol
C. 2 mol
D. 18 mol
Q16. The empirical formula of a compound represents the:
A. Actual number of atoms in one molecule
B. Simplest whole-number ratio of atoms
C. Total molecular mass
D. Number of molecules in one mole
Q17. Which of the following is a limiting reagent?
A. A reactant that remains unchanged
B. A reactant that determines the maximum amount of product formed
C. A catalyst that speeds up a reaction
D. A product formed after the reaction
Q18. The SI unit of amount of substance is:
A. Gram
B. Kilogram
C. Mole
D. Litre
Q19. The percentage by mass of an element in a compound is calculated using:
A. Mass of the element divided by molar mass of the compound, multiplied by 100
B. Molar mass divided by volume, multiplied by 100
C. Volume divided by mass, multiplied by 100
D. Number of molecules divided by density
Q20. The molarity of a solution is defined as the number of:
A. Moles of solute per kilogram of solvent
B. Grams of solute per litre of solvent
C. Moles of solute per litre of solution
D. Molecules of solvent per mole of solute
Numerical Questions
Q21. Calculate the number of moles present in 11 g of carbon dioxide.
Given:
[ M(CO_2)=44\ \text{g mol}^{-1} ]
Q22. How many molecules are present in 0.5 mol of oxygen gas?
Use Avogadro's constant:
[ N_A=6.022\times10^{23}\ \text{mol}^{-1} ]
Q23. Assertion–Reason
Assertion (A): One mole of every substance contains the same number of specified elementary entities.
Reason (R): One mole contains approximately 6.022\times10^{23} specified entities.
Choose the correct answer:
A. Both A and R are true, and R correctly explains A.
B. Both A and R are true, but R does not correctly explain A.
C. A is true, but R is false.
D. A is false, but R is true.
Q24. A solution contains 2 moles of solute in 500 mL of solution. Its molarity is:
A. 1 M
B. 2 M
C. 4 M
D. 0.25 M
Q25. A compound contains 40% carbon, 6.67% hydrogen and 53.33% oxygen by mass. What is its empirical formula?
Use atomic masses: C = 12, H = 1, O = 16.
A. CH_2O
B. C_2H_4O
C. CHO
D. CH_4O
Q26. A reaction requires 2 moles of hydrogen for every 1 mole of oxygen to form water. If 3 moles of hydrogen react with 2 moles of oxygen, the limiting reagent is:
A. Hydrogen
B. Oxygen
C. Water
D. Neither reactant
Chemistry Formula Revision
Number of moles:
[ n=\frac{\text{Given mass}}{\text{Molar mass}} ]
Number of particles:
[ N=nN_A ]
Molarity:
[ M=\frac{\text{Moles of solute}}{\text{Volume of solution in litres}} ]
Percentage by mass:
[ %\text{ by mass} =\frac{\text{Mass of element in the compound}}{\text{Molar mass of compound}}\times100 ]
For a pure compound, the molecular formula is an integer multiple of the empirical formula:
[ \text{Molecular formula}=(\text{Empirical formula})_n ]
[ n=\frac{\text{Molecular molar mass}}{\text{Empirical formula mass}} ]
SECTION C: BIOLOGY
Topic: Organisms and Populations
Multiple-Choice Questions
Q27. The branch of ecology that studies interactions between organisms and their environment is concerned with:
A. Only the internal structure of cells
B. Relationships between organisms and environmental factors
C. Only the chemical composition of rocks
D. Only the classification of minerals
Q28. Which of the following is an abiotic environmental factor?
A. Predation
B. Competition
C. Temperature
D. Parasitism
Q29. The population growth equation under ideal conditions, with unlimited resources, is commonly expressed as:
A. \frac{dN}{dt}=rN
B. \frac{dN}{dt}=-rN
C. \frac{dN}{dt}=K-N
D. \frac{dN}{dt}=0 in all cases
Q30. The maximum population size that an environment can sustain over time is called:
A. Natality
B. Mortality
C. Carrying capacity
D. Immigration
Q31. The interaction in which one species benefits while the other is neither significantly helped nor harmed is called:
A. Mutualism
B. Commensalism
C. Parasitism
D. Competition
Q32. In mutualism:
A. Both species benefit
B. Both species are harmed
C. One benefits and the other is harmed
D. Neither species benefits
Q33. Which population interaction involves two species competing for limited resources?
A. Mutualism
B. Commensalism
C. Competition
D. Neutralism
Q34. In logistic population growth, the growth rate slows as the population approaches:
A. Zero population size only
B. Carrying capacity
C. The maximum possible birth rate in every case
D. Infinite population size
Assertion–Reason
**Q35. Assertion (A): Temperature can influence the distribution of organisms.
Reason (R): Organisms differ in their tolerance ranges for environmental temperatures.
Choose the correct answer:
A. Both A and R are true, and R correctly explains A.
B. Both A and R are true, but R does not correctly explain A.
C. A is true, but R is false.
D. A is false, but R is true.
Q36. Which of the following is generally characteristic of a rapidly growing population with an abundance of resources?
A. High reproductive potential
B. No reproduction
C. Permanent absence of immigration and emigration
D. An inevitable immediate population decline
Q37. The interaction between a parasite and its host is usually classified as:
A. Mutualism
B. Commensalism
C. Parasitism
D. Competition
Q38. Which equation represents logistic population growth?
A. \frac{dN}{dt}=rN
B. \frac{dN}{dt}=rN\left(\frac{K-N}{K}\right)
C. \frac{dN}{dt}=-K
D. \frac{dN}{dt}=r+K
Biology Revision Notes
Population growth under ideal conditions:
[ \frac{dN}{dt}=rN ]
This is the exponential growth model.
Logistic growth:
[ \frac{dN}{dt}=rN\left(\frac{K-N}{K}\right) ]
Where:
N = population size
r = intrinsic rate of natural increase
K = carrying capacity
Major population interactions:
Mutualism: both species benefit (+/+)
Competition: both species are negatively affected by competing for resources (-/-)
Predation: predator benefits and prey is harmed (+/-)
Parasitism: parasite benefits and host is harmed (+/-)
Commensalism: one benefits while the other is largely unaffected (+/0)
The actual effects of ecological interactions depend on the organisms and environmental conditions.
COMPLETE ANSWER KEY
Question
Answer
Question
Answer
Q1
B
Q20
C
Q2
A
Q21
0.25 mol
Q3
C
Q22
3.011\times10^{23} molecules
Q4
B
Q23
A
Q5
C
Q24
C
Q6
D
Q25
A
Q7
C
Q26
A
Q8
C
Q27
B
Q9
-3.4 eV
Q28
C
Q10
1.89 eV (approx.)
Q29
A
Q11
A
Q30
C
Q12
C
Q31
B
Q13
B
Q32
A
Q14
D
Q33
C
Q15
B
Q34
B
Q16
B
Q35
A
Q17
B
Q36
A
Q18
C
Q37
C
Q19
A
Q38
B
DETAILED NUMERICAL SOLUTIONS
Physics Q9
[ E_2=\frac{-13.6}{2^2} ]
[ E_2=\frac{-13.6}{4} ]
[ \boxed{E_2=-3.4\ \text{eV}} ]
Physics Q10
Energy at n=3:
[ E_3=\frac{-13.6}{9}\approx-1.51\ \text{eV} ]
Energy at n=2:
[ E_2=-3.4\ \text{eV} ]
Photon energy emitted:
[ E_\gamma=E_3-E_2 ]
[ E_\gamma=(-1.51)-(-3.4) ]
[ \boxed{E_\gamma\approx1.89\ \text{eV}} ]
Chemistry Q21
[ n=\frac{11}{44} ]
[ \boxed{n=0.25\ \text{mol}} ]
Chemistry Q22
[ N=nN_A ]
[ N=0.5\times6.022\times10^{23} ]
[ \boxed{N=3.011\times10^{23}\text{ molecules}} ]
Chemistry Q24
Convert the volume into litres:
[ 500\text{ mL}=0.5\text{ L} ]
[ M=\frac{2}{0.5} ]
[ \boxed{M=4\text{ M}} ]
Chemistry Q25
Assume 100 g of compound.
Moles of carbon:
[ \frac{40}{12}=3.33 ]
Moles of hydrogen:
[ \frac{6.67}{1}=6.67 ]
Moles of oxygen:
[ \frac{53.33}{16}=3.33 ]
Divide by the smallest value:
[ C:H:O\approx1:2:1 ]
[ \boxed{CH_2O} ]
Chemistry Q26
The balanced reaction is:
[ 2H_2+O_2\rightarrow2H_2O ]
Three moles of hydrogen require:
[ \frac{3}{2}=1.5\text{ mol of }O_2 ]
Since 2 moles of oxygen are available, oxygen is in excess and hydrogen is the limiting reagent.
Answer: Hydrogen.
SEVEN-DAY REVISION PLAN
Day 1: Revise Bohr's model, energy levels and atomic spectra.
Day 2: Practise hydrogen atom numerical problems.
Day 3: Revise mole concept, molar mass and Avogadro's constant.
Day 4: Practise empirical formula, molarity and limiting reagent problems.
Day 5: Revise population growth and environmental factors.
Day 6: Revise population interactions and ecological relationships.
Day 7: Attempt all 38 questions under timed conditions and analyse mistakes.
DISCLAIMER
This practice set has been independently prepared for educational purposes. It is not an official NTA publication, and the appearance of these questions in NEET 2027 is not guaranteed. Students should check the latest official NEET syllabus and notifications and use the prescribed NCERT textbooks for preparation. No examination score, rank or admission outcome is guaranteed.
META DESCRIPTION
Practise for NEET 2027 with 38 subject-wise questions on Atoms, Some Basic Concepts of Chemistry, and Organisms and Populations. Includes MCQs, numerical problems, assertion–reason questions, answer keys, explanations and revision formulas.
KEYWORDS
NEET 2027, NEET 2027 practice questions, Atoms MCQs, Bohr model questions, Mole Concept, Limiting Reagent, Organisms and Populations, NEET Biology MCQs, NCERT practice, NEET numerical questions.
HASHTAGS
#NEET2027 #NEETPreparation #NEETPractice #Physics #Atoms #Chemistry #MoleConcept #Biology #OrganismsAndPopulations #NCERT #NEETQuestions
Keep learning, keep practising, and keep improving. Every carefully corrected mistake is a step towards stronger preparation.
বন্ধু, Part 90 সম্পূর্ণ হলো। মনে রেখো, শুধু উত্তর মুখস্থ না করে প্রতিটি উত্তরের কারণ বোঝার চেষ্টা করবে। সেটাই তোমার প্রস্তুতিকে আরও শক্তিশালী করবে।
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