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JEE Advanced 2025 Paper 1 Online
Numerical
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Consider an electron in the $n=3$ orbit of a hydrogen-like atom with atomic number $Z$. At absolute temperature $T$, a neutron having thermal energy $k_{\mathrm{B}} T$ has the same de Broglie wavelength as that of this electron. If this temperature is given by $T=\frac{Z^2 h^2}{\alpha \pi^2 a_0^2 m_{\mathrm{N}} k_{\mathrm{B}}}$, (where $h$ is the Planck's constant, $k_B$ is the Boltzmann constant, $m_{\mathrm{N}}$ is the mass of the neutron and $a_0$ is the first Bohr radius of hydrogen atom) then the value of $\alpha$ is ______.
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JEE Advanced 2025 Paper 1 Online
MCQ (Single Correct Answer)
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List-I shows four configurations, each consisting of a pair of ideal electric dipoles. Each dipole has a dipole moment of magnitude $p$, oriented as marked by arrows in the figures. In all the configurations the dipoles are fixed such that they are at a distance $2 r$ apart along the $x$ direction. The midpoint of the line joining the two dipoles is $X$. The possible resultant electric fields $\vec{E}$ at $X$ 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) JEE Advanced 2025 Paper 1 Online Physics - Electrostatics Question 1 English 1 (1) $$ \vec{E}=0 $$
(Q) JEE Advanced 2025 Paper 1 Online Physics - Electrostatics Question 1 English 2 (2) $\displaystyle \vec{E} = -\,\frac{p}{2\pi\epsilon_0\,r^3}\,\hat{\jmath}$
(R) JEE Advanced 2025 Paper 1 Online Physics - Electrostatics Question 1 English 3 (3) $\displaystyle \vec{E} = -\,\frac{p}{4\pi\epsilon_0\,r^3}\,(\hat{\imath} - \hat{\jmath})$
(S) JEE Advanced 2025 Paper 1 Online Physics - Electrostatics Question 1 English 4 (4) $\displaystyle \vec{E} = \frac{p}{4\pi\epsilon_0\,r^3}\,(2\hat{\imath} - \hat{\jmath})$
(5) $\displaystyle \vec{E} = \frac{p}{\pi\epsilon_0\,r^3}\,\hat{\imath}$
A
$ \mathrm{P} \rightarrow 3, \mathrm{Q} \rightarrow 1, \mathrm{R} \rightarrow 2, \mathrm{~S} \rightarrow 4$
B
$\mathrm{P} \rightarrow 4, \mathrm{Q} \rightarrow 5, \mathrm{R} \rightarrow 3, \mathrm{~S} \rightarrow 1$
C
$\mathrm{P} \rightarrow 2, \mathrm{Q} \rightarrow 1, \mathrm{R} \rightarrow 4, \mathrm{~S} \rightarrow 5$
D
$\mathrm{P} \rightarrow 2, \mathrm{Q} \rightarrow 1, \mathrm{R} \rightarrow 3, \mathrm{~S} \rightarrow 5$
3
JEE Advanced 2025 Paper 1 Online
MCQ (Single Correct Answer)
+4
-1
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A circuit with an electrical load having impedance $Z$ is connected with an AC source as shown in the diagram. The source voltage varies in time as $V(t)=300 \sin (400 t) \mathrm{V}$, where $t$ is time in s . List-I shows various options for the load. The possible currents $i(t)$ in the circuit as a function of time are given in List-II.

JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 1

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

List–I List–II
(P) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 2 (1) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 3
(Q) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 4 (2) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 5
(R) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 6 (3) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 7
(S) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 8 (4) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 9
(5) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 10
A
$ \mathrm{P} \rightarrow 3, \mathrm{Q} \rightarrow 5, \mathrm{R} \rightarrow 2, \mathrm{~S} \rightarrow 1$
B
$\mathrm{P} \rightarrow 1, \mathrm{Q} \rightarrow 5, \mathrm{R} \rightarrow 2, \mathrm{~S} \rightarrow 3$
C
$\mathrm{P} \rightarrow 3, \mathrm{Q} \rightarrow 4, \mathrm{R} \rightarrow 2, \mathrm{~S} \rightarrow 1$
D
$\mathrm{P} \rightarrow 1, \mathrm{Q} \rightarrow 4, \mathrm{R} \rightarrow 2, \mathrm{~S} \rightarrow 5$
4
JEE Advanced 2025 Paper 1 Online
MCQ (Single Correct Answer)
+4
-1
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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

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