An electron, practically at rest, is initially accelerated through a potential difference of 100 volts. It then has a de Broglie wavelength=$\lambda$1Å. It then get retarded through 19 volts and then it has wavelength $\lambda$2 Å. A further retardation through 32 volts changes the wavelength to $\lambda$3.

What is ($\lambda$3-$\lambda$2)/$\lambda$1?

(A) 20/41

(B) 10/63

(C) 20/63

(D) 10/41

Concept Questions :-

de Broglie Equation
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Difficulty Level:

Which of the following has the maximum number of  unpaired electons-

(A) Mg2+

(B) Ti3+

(C) V3+

(D) Fe2+

Concept Questions :-

Number of E/P/N
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Difficulty Level:

There are three energy levels in an atom. How many spectral lines are possible in its emission spectra?

(A) One

(B) Two

(C) Three

(D) Four

Concept Questions :-

Type of Spectra
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Difficulty Level:

Azimuthal quantum number defines -

(A) e/m ratio of electron

(B) Spin of electron

(C) Angular momentum of electron

(D) Magnetic momentum of electron

Concept Questions :-

Quantum Numbers
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Difficulty Level:

For the energy levels in an atom, which one of the following statements is correct -

(A) There are seven principal electron energy levels

(B) The second principal energy level can have four ‘sub energy levels and contains a maximum of eight electrons

(C) The energy level can have maximum of 32 electrons

(D) The 4s sub-energy level is at a higher energy than the 3d sub-energy level

Concept Questions :-

Hydrogen Spectra
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Difficulty Level:

Arrange the following particles in increasing order of values of e/m ratio: Electron(e), proton(p), neutron(n) and $\mathrm{\alpha }$-particle($\mathrm{\alpha }$)

(A) n,p,e,$\mathrm{\alpha }$

(B) n,$\mathrm{\alpha }$,p,e

(C) n,p,$\mathrm{\alpha }$,e

(D) e,p,n,$\mathrm{\alpha }$

Concept Questions :-

introduction
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Difficulty Level:

The increasing order of energy of electromagnetic radiation can be represented as

(A) microwave < infrared < visible < X-ray

(B) X-ray < visible < infrared < microwave

(C) microwave < infrared < visible < radiowaves

(D) X-ray < infrared < visible < microwave

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The wavelength of the photoelectric threshold of a metal is 230 nm. Determine the K.E. of photoelectron ejected from the surface by UV radiation emitted from the second longest wavelength transition (downward) of electron in Lyman series of the atomic spectrum of hydrogen. (R=1.09677 x 107 m-1)

(A) 0.074 x 10-16 J

(B) 1.074 x 10-18J

(C) 6.213 × 10-18 J

(D) 7.123 x 10-10J

Concept Questions :-

Hydrogen Spectra
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Difficulty Level:

Beryllium's fourth electron will have the four quantum numbers :

n               $\mathcal{l}$               m             s

(A)                    1               0                0             1/2

(B)                    1               1                1             1/2

(C)                    2               0                0             -1/2

(D)                    2               1                 0             +1/2

Concept Questions :-

Quantum Numbers
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Difficulty Level:

Mass of neutron is ........................times the mass of electron-

(A) 1840

(B) 1480

(C) 2000

(D) None

Concept Questions :-

introduction