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Structure of Atom · Question 13

JEE Main 2026 (Online) 28th January Morning ShiftMCQEasy📈 Topic in 26% papers+4−1
1

The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series. (R = Rydberg constant)

  1. 5R36, 3R16, 21R100
  2. 7R144, 3R16, 16R255
  3. 3R4, 3R16, 7R144
  4. 5R36, 8R9, 15R16

Answer

(1) 5R36, 3R16, 21R100

Solution

For the Balmer series of hydrogen: = R ( 122 - 1n2 ), n = 3, 4, 5, …

n = 3: = R ( 14 - 19 ) = 5R36

n = 4: = R ( 14 - 116 ) = 3R16

n = 5: = R ( 14 - 125 ) = 21R100

These are the three lines of set (1).

(Other sets contain lines of other series, e.g. 3R4, 8R9, 15R16 belong to the Lyman series and 7R144 to the Paschen series.)

Answer: (1)

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2

[figure] Figure 1. electron probability density for 2s orbital [figure] Figure 2. wave function for 2s orbital Which of the following point in Figure 2 most accurately represents the nodal surface as shown in Figure 1?

  1. D
  2. B
  3. C
  4. A
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3

The wavelength of photon 'A' is 400 nm. The frequency of photon 'B' is 1016 s-1. The wave number of photon 'C' is 104 cm-1. The correct order of energy of these photons is :

  1. A > C > B
  2. C > B > A
  3. B > A > C
  4. A > B > C
JEE Main 2026 (Online) 28th January Evening Shift
4

Two positively charged particles m1 and m2 have been accelerated across the same potential difference of 200 kV as shown below. [figure] [Given mass of m1 = 1 amu and m2 = 4 amu] The de Broglie wavelength of m1 will be x times of m2. The value of x is (nearest integer)

JEE Main 2026 (Online) 28th January Evening Shift
5

The hydrogen spectrum consists of several spectral lines in Lyman series (L1, L2, L3 ; L1 has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series (B1, B2, B3 ; B1 has lowest energy among Balmer lines). The energy of L1 is x times the energy of B1. The value of x is 10-1. (Nearest integer)

JEE Main 2026 (Online) 24th January Morning Shift
6

The wavelength of spectral line obtained in the spectrum of Li2+ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is

  1. 1.14 10-6 cm
  2. 2.28 10-6 cm
  3. 1.14 10-7 cm
  4. 2.28 10-7 cm
JEE Main 2026 (Online) 24th January Evening Shift
7

Given, (A) n = 5, ml = -1 (B) n = 3, l = 2, ml = -1, ms = + 12 The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :

  1. 4 and 1
  2. 2 and 4
  3. 26 and 1
  4. 8 and 1
JEE Main 2026 (Online) 23rd January Morning Shift
8

Which of the following statements regarding the energy of the stationary state is true in the following one-electron systems ?

  1. +2.18 10-18 J for second orbit of He+ ion
  2. +8.72 10-18 J for first orbit of He+ ion
  3. -1.09 10-18 J for second orbit of H atom.
  4. -2.18 10-18 J for third orbit of Li2+ ion
JEE Main 2026 (Online) 23rd January Morning Shift
9

The work functions of two metals (MA and MB) are in the 1 : 2 ratio. When these metals are exposed to photons of energy 6 eV, the kinetic energy of liberated electrons of MA : MB is in the ratio of 2.642 : 1. The work functions (in eV) of MA and MB are respectively.

  1. 3.1, 6.2
  2. 1.5, 3.0
  3. 2.3, 4.6
  4. 1.4, 2.8
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10

Identify the INCORRECT statements from the following : Choose the correct answer from the options given below :

  1. A and D Only
  2. A and C Only
  3. A and B Only
  4. B and C Only
JEE Main 2026 (Online) 23rd January Evening Shift
11

The energy required by electrons, present in the first Bohr orbit of hydrogen atom to be excited to second Bohr orbit is J mol-1. Given: RH = 2.18 10-11 ergs.

  1. 9.835 1012
  2. 1.635 10-11
  3. 1.635 10-18
  4. 9.835 105
JEE Main 2026 (Online) 22nd January Morning Shift

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