According to Bohr's theory, the angular momentum for an electron

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 Multiple Choice QuestionsMultiple Choice Questions

41.

The electronic transitions from n = 2 to n= 1 will produce shortest wavelength in (where n = principal quantum state)

  • Li2+ 

  • He+

  • H

  • H+


42.

In the following electron-dot structure, calculate the formal charge from left to right nitrogen atom; 

  • -1, -1, +1

  • -1, +1, -1

  • +1, -1, -1

  • +1, -1, +1


43.

A radioactive atom YXM emits two a particles and one B particle successively. The number of neutrons in the nucleus of the product will be

  • X - 4 - Y

  • X - Y - 5

  • X - Y - 3

  • X - Y - 6


44.

For a particular value of azimuthal quantum number, the total number of magnetic quantum number values are given by

  • l = m + 12

  • l = m - 12

  • l = 2m + 12

  • m = 2l + 12


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45.

What is the wavelength of an α-particle having mass 6.6 × 10-27 kg moving with a speed of 105 cms-1? ( h = 6.6 × 10-34 kgm2 - s)?

  • 2 × 10-12 m

  • 3 × 10-10 m

  • 1 × 10-10 m

  • 2 × 10-10 m


46.

With what velocity should an α-particle travel towards the nucleus of a copper atom to arrive at a distance of 10-13m from the nucleus of the copper atom?(K = 9x 10Nm2/C2 (Mass of α-particle = 6.64 x 10-27kg).

  • 634 x 106 ms-1

  • 634 x10ms-1

  • 5.34 x 106 ms-1

  • 534 x 105 ms-1


47.

What is the ratio of the velocities of CH4 and O2 molecules so that they are associated with de-Broglie waves of equal wavelengths?

  • 1:2

  • 2: 1

  • 3: 2

  • 1: 2


48.

What is the value of the spin quantum number of the last electron ford d9 -configuration ?

  • 0

  • -12

  • 12

  • 1


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49.

The ratio of slopes of Kmax vs V and V0 vs v curves in the photoelectric effects gives (v = frequency, Kmax = maximum kinetic energy, v0 = stopping potential)

  • the ratio of Planck's constant of electronic charge

  • work function

  • Planck's constant

  • charge of electron


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50.

According to Bohr's theory, the angular momentum for an electron of 3rd orbit is

  • 3h

  • 1.5h

  • 9h

  • 2hπ


A.

3h

Angular momentum, mvr = nh2π=3 ×h2π=1.5hπ                                             =3hh=h2π


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