JEE Advanced 2026 Paper 2 Online | Atoms and Nuclei Question 1 | Physics

1

JEE Advanced 2026 Paper 2 Online

MCQ (Single Correct Answer)

+3

-1

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 :

A

$ \frac{\alpha E_0}{ms} (1 - e^{-\lambda t}) $

B

$ \frac{\alpha E_0}{ms} (e^{\lambda t} - 1) $

C

$ \frac{\lambda E_0}{ms} (1 - e^{-\lambda t}) $

D

$ \frac{E_0}{ms} (\alpha - \lambda e^{-\lambda t}) $

2

JEE Advanced 2025 Paper 1 Online

MCQ (Single Correct Answer)

+4

-1

List-I shows various functional dependencies of energy $(E)$ on the atomic number $(Z)$. Energies associated with certain phenomena are given in List-II.

Choose the option that describes the correct match between the entries in List-I to those in List-II.

List–I	List–II
(P) $E \propto Z^2$	(1) energy of characteristic x-rays
(Q) $E \propto (Z - 1)^2$	(2) electrostatic part of the nuclear binding energy for stable nuclei with mass numbers in the range 30 to 170
(R) $E \propto Z(Z - 1)$	(3) energy of continuous x-rays
(S) $E$ is practically independent of $Z$	(4) average nuclear binding energy per nucleon for stable nuclei with mass number in the range 30 to 170
	(5) energy of radiation due to electronic transitions from hydrogen-like atoms

A

P→4, Q→3, R→1, S→2

B

P→5, Q→2, R→1, S→4

C

P→5, Q→1, R→2, S→4

D

P→3, Q→2, R→1, S→5

3

JEE Advanced 2023 Paper 1 Online

MCQ (Single Correct Answer)

+3

-1

List-I shows different radioactive decay processes and List-II provides possible emitted particles. Match each entry in List-I with an appropriate entry from List-II, and choose the correct option.

List - I	List - II
(P) ${ }_{92}^{238} U \rightarrow{ }_{91}^{234} \mathrm{~Pa}$	(1) one $\alpha$ particle and one $\beta^{+}$particle
(Q) ${ }_{82}^{214} \mathrm{~Pb} \rightarrow{ }_{82}^{210} \mathrm{~Pb}$	(2) three $\beta^{-}$particles and one $\alpha$ particle
(R) ${ }_{81}^{210} \mathrm{Tl} \rightarrow{ }_{82}^{206} \mathrm{~Pb}$	(3) two $\beta^{-}$particles and one $\alpha$ particle
(S) ${ }_{91}^{228} \mathrm{~Pa} \rightarrow{ }_{88}^{224} \mathrm{Ra}$	(4) one $\alpha$ particle and one $\beta^{-}$particle
	(5) one $\alpha$ particle and two $\beta^{+}$particles

A

$P \rightarrow 4, Q \rightarrow 3, R \rightarrow 2, S \rightarrow 1$

B

$P \rightarrow 4, Q \rightarrow 1, R \rightarrow 2, S \rightarrow 5$

C

$P \rightarrow 5, Q \rightarrow 3, R \rightarrow 1, S \rightarrow 4$

D

$P \rightarrow 5, Q \rightarrow 1, R \rightarrow 3, S \rightarrow 2$

4

JEE Advanced 2021 Paper 1 Online

MCQ (Single Correct Answer)

+3

-1

A heavy nucleus Q of half-life 20 minutes undergoes alpha-decay with probability of 60% and beta-decay with probability of 40%. Initially, the number of Q nuclei is 1000. The number of alpha-decays of Q in the first one hour is

A

50

B

75

C

350

D

525

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