Atoms  MCQs

MCQs of Atoms

Showing 11 to 20 out of 146 Questions
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11.
What is the angular momentum of an electron of Li-atom in n = 5 orbit.
(a) 5.27 × 10-1 Js
(b) 6.625 × 10-34 Js
(c) 1.325 × 10-34 Js
(d) 16.56 × 10-34 Js
Answer:

Option (a)

12.
The wavelengh of the first line of Lyman series is λ. The wavelengh of the first line in Balmer series is _____ .
(a) 275λ
(b) 527λ
(c) 92λ
(d) 25λ
Answer:

Option (a)

13.
The difference of wave numbers of lines with maximum and minimum wavelengths in Balmer series of hydrogen atom is _____ m-1. (R = 1.097 × 107 m-1)
(a) 1.219 × 106
(b) 1.219 × 10-6
(c) 1219
(d) 1.219 × 107
Answer:

Option (a)

14.
In hydrogen atom, an electron makes transition from n = 3 to n = 1 state in time interval of 1.2 × 10-8 s calculate average toque (in Nm) acting on the electron during this transition.
(a) 1.055 × 10-26
(b) 4.40 × 10-27
(c) 1.7 × 10-26
(d) 8.79 × 10-27
Answer:

Option (c)

15.
In which of the following system will the radius of the 2nd orbit be minimum ?
(a) H- atom
(b) Mg+11
(c) He+
(d) B- atom
Answer:

Option (b)

16.
The ionization potentials of hydrogenic ions A and B are VA and VB , respectively. Now if VB > VA then _____
(a) rA > rB
(b) rA < rB
(c) rA = rB
(d) none of the above
Answer:

Option (a)

17.
The operating voltage in Coolidge tube is 105 V. The speed of X-rays produced is ____ms-1.
(a) 2 × 108
(b) 105
(c) 106
(d) 3 × 108
Answer:

Option (d)

18.
The wavelength of Kα spectral line is λ for an element of atomic number 43. The wavelength of Kα line for an element with atomic number 29 is ____ λ.
(a) 4329
(b) 4228
(c) 94
(d) 49
Answer:

Option (c)

19.
If f1, f2 and f3 are the frequencies corresponding to Kα, Kβ and Lα X-rays for the given target. Then ____
(a) f1 = f2 = f3
(b) f1 - f2 = f3
(c) f2 = f1 + f3
(d) f3 - f2 = f1
Answer:

Option (c)

20.
The spectral lines of pfund series lies in the _____ region.
(a) ultraviolet
(b) infrared
(c) visible light
(d) none of these
Answer:

Option (b)

Showing 11 to 20 out of 146 Questions
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