Free physics question bank
radioactivity and law of decay questions with solutions
Practice Nuclear physics for JEE Main, JEE Advanced, NEET, and Classes 11–12. Attempt each question, then open it for the full solution.
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- NumericmediumNuclear physics
A radioactive parent isotope P decays into a stable daughter isotope D. At the time a mineral crystallised, no daughter isotope was present. At present the measured number ratio is N(D): N(P) = 15:1. If the half-life of P is 500 million years, find the age of the mineral in million years.
JEE MainsNEETJEE Advanced
Open question & full solution → - NumericeasyNuclear physics
A parent nucleus has total binding energy 1700 MeV. After α-decay, the daughter nucleus has total binding energy 1680 MeV and the α-particle has binding energy 28 MeV. If the decay energy release is N MeV, find N.
JEE MainsNEETJEE Advanced
Open question & full solution → - MCQeasyNuclear physics
A heavy parent nucleus initially at rest emits an α-particle. The daughter nucleus has mass number 206. Neglect the small difference between nuclear mass and mass number. What is the approximate ratio of α-particle kinetic energy to daughter-nucleus recoil kinetic energy?
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JEE MainsNEETJEE Advanced
Open question & full solution → - NumericmediumNuclear physics
A stationary radioactive nucleus of mass number 120 undergoes α-decay and releases a total energy of 30 MeV. Assume the daughter and α-particle are non-relativistic and their masses are proportional to their mass numbers. If the kinetic energy of the α-particle is N MeV, find N.
JEE MainsNEETJEE Advanced
Open question & full solution → - NumericmediumNuclear physics
In a successive decay chain A → B → C, the decay constant of A is twice the decay constant of B. At the instant when the number of B nuclei is maximum, the number of A nuclei is 400. Find the number of B nuclei at that instant.
JEE MainsNEETJEE Advanced
Open question & full solution → - MCQmediumNuclear physics
A radioactive nucleus ²⁵²₉₈X, initially in its ground state, undergoes the following sequence: it emits three α-particles, then two β⁻-particles, then one β⁺-particle, and finally one γ-photon. No other particles are emitted. Which pair gives the mass number A and atomic number Z of the final daughter nucleus?
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JEE MainsNEETJEE Advanced
Open question & full solution → - MCQeasyNuclear physics
Substance A has atomic mass number 16 and half life of 1 day. Another substance B has atomic mass number 32 and half life of 1/2 day. If both A and B simultaneously start undergoing radioactivity at the same time with initial mass 320 g each, how many total atoms of A and B combined would be left after 2 days?
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JEE Mains29 January 2023Shift 2Evening Shift
Open question & full solution → - MCQmediumNuclear physics
A radioactive nucleus has mean life τ. What is the probability that it survives up to time τ but decays before time 3τ?
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JEE MainsNEETJEE Advanced
Open question & full solution → - NumericmediumNuclear physics
A parent nucleus initially at rest undergoes β⁻-decay. In one event, the emitted electron has momentum magnitude 1.2 MeV·c⁻¹ and the antineutrino has momentum magnitude 0.9 MeV·c⁻¹. The angle between their momenta is 60°. If the daughter recoil momentum satisfies p(D)² = [N ÷ 100](MeV·c⁻¹)², find N.
JEE MainsNEETJEE Advanced
Open question & full solution → - MCQmediumNuclear physics
A nuclear reactor starts producing a radioactive nuclide X from t = 0, at a constant rate of α per second. Each decay of X produces energy E₀, which is utilized to heat a liquid of mass m and specific heat s. Assuming no heat loss from the liquid and taking λ as the decay constant of X, the rate of increase in the temperature of the liquid is:
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JEE Advanced2026Paper 2
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