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JEE Main 2026 (Online) 24th January Morning Shift
Numerical
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-1
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The hydrogen spectrum consists of several spectral lines in Lyman series $\left(L_1, L_2\right.$, $\mathrm{L}_3 \ldots ; \mathrm{L}_1$ has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series $\left(\mathrm{B}_1, \mathrm{~B}_2, \mathrm{~B}_3 \ldots ; \mathrm{B}_1\right.$ has lowest energy among Balmer lines). The energy of $L_1$ is $x$ times the energy of $B_1$. The value of $x$ is $\_\_\_\_$ $\times 10^{-1}$

. (Nearest integer)

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2
JEE Main 2025 (Online) 8th April Evening Shift
Numerical
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-1
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The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV.

The magnitude of energy value of an electron in the first excited state of Be3+ is ________ eV (nearest integer value).

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3
JEE Main 2024 (Online) 9th April Evening Shift
Numerical
+4
-1
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Based on Heisenberg's uncertainty principle, the uncertainty in the velocity of the electron to be found within an atomic nucleus of diameter $$10^{-15} \mathrm{~m}$$ is ________ $$\times 10^9 \mathrm{~ms}^{-1}$$ (nearest integer)

[Given : mass of electron $$=9.1 \times 10^{-31} \mathrm{~kg}$$, Plank's constant $$(h)=6.626 \times 10^{-34} \mathrm{Js}$$] (Value of $$\pi=3.14$$)

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4
JEE Main 2024 (Online) 8th April Evening Shift
Numerical
+4
-1
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Wavenumber for a radiation having 5800 $$\mathop A\limits^o $$ wavelength is $$x \times 10 \mathrm{~cm}^{-1}$$ The value of $$x$$ is ________. (Integer answer)

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