1
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
The de Broglie wavelength of an electron in the 4th Bohr orbit is :
A
2$$\pi$$a0
B
6$$\pi$$a0
C
8$$\pi$$a0
D
4$$\pi$$a0
2
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
The radius of the second Bohr orbit, in terms of the Bohr radius, a0, in Li2+ is :
A
$${{2{a_0}} \over 9}$$
B
$${{2{a_0}} \over 3}$$
C
$${{4{a_0}} \over 9}$$
D
$${{4{a_0}} \over 3}$$
3
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
Hydrogen has three isotopes (A), (B) and (C). If the number of neutron(s) in (A), (B) and (C) respectively, are (x), (y) and (z), the sum of (x), (y) an (z) is :
A
3
B
1
C
4
D
2
4
JEE Main 2020 (Online) 8th January Morning Slot
+4
-1
For the Balmer series in the spectrum of H atom,
$$\overline \nu = {R_H}\left\{ {{1 \over {n_1^2}} - {1 \over {n_2^2}}} \right\}$$, the correct statements among (I) to (IV) are :
(I) As wavelength decreases, the lines in the series converge
(II) The integer n1 is equal to 2
(III) The lines of longest wavelength corresponds to n2 = 3
(IV) The ionization energy of hydrogen can be calculated from wave number of these lines
A
(II), (III), (IV)
B
(I), (II), (III)
C
(I), (III), (IV)
D
(I), (II), (IV)
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