1
WB JEE 2023
MCQ (More than One Correct Answer)
+2
-0
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A uniform magnetic field B exists in a region. An electron of charge q and mass m moving with velocity v enters the region in a direction perpendicular to the magnetic field. Considering Bohr angular momentum quantization, which of the following statements is/are true?

A
The radius of nth orbit $$\mathrm{r_n~\infty ~\sqrt n}$$.
B
The minimum velocity of the electron is $$\frac{\sqrt{\mathrm{qB} \hbar}}{\mathrm{m}}$$.
C
Energy of the $$\mathrm{n}^{\text {th }}$$ level $$E_{n} ~\infty~n$$.
D
Transition frequency $$\omega$$ between two successive levels is independent of n.
2
WB JEE 2022
MCQ (More than One Correct Answer)
+2
-0
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A sample of hydrogen atom in its ground state is radiated with photons of 10.2 eV energies. The radiation from the sample is absorbed by excited ionized He+. Thenwhich of the following statement/s is/are true?

A
He+ electron moves from n = 2 to n = 4.
B
In the He+ emission spectra, there will be 6 lines.
C
Smallest wavelength of He+ spectrum is obtained when transition taken place from n = 4 to n = 3.
D
He+ electron moves from n = 2 to n = 3.
3
WB JEE 2017
MCQ (More than One Correct Answer)
+2
-0
Change Language
Let vn and En be the respective speed and energy of an electron in the nth orbit of radius rn, in a hydrogen atom, as predicted by Bohr's model. Then
A
plot of $${{{E_n}{r_n}} \over {{E_1}{r_1}}}$$ as a function of n is a straight line of slope 0
B
plot of $${{{r_n}{v_n}} \over {{r_1}{v_1}}}$$ as a function of n is a straight line of slope 1
C
plot of ln$$\left( {{{{r_n}} \over {{r_1}}}} \right)$$ as a function of ln (n) is a straight line of slope 2
D
plot of ln $$\left( {{{{r_n}{E_1}} \over {{E_n}{r_1}}}} \right)$$ as a function of ln (n) is a straight line of slope 4
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