Question # 1

In Millikan method for determination of charge on electron the air in the chamber is ionized by

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Protons

Electric field

X-rays

a - particles

With increasing principle quantum number, the energy difference between adjacent energy levels in H atom

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Decreases

Increases

Remains constant

Decreases for low value of Z and increase for higher value of Z

Which quantum number is sufficient to describe the electron is hydrogen atom?

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l

n

m

s

The value of charge on electron is

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1.602 x 10^-19coulombs

1.602 x 10^-18coulombs

1.602 x 10^-17coulombs

1.602 x 10^-16coulombs

The radiations with wavelength shorter than violet light are called

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Ultraviolet

Infrared

Microwave

Radio frequency

No cathode rays are produced in the discharged tube when gas is under ordinary pressure even if voltage of 5000 to 10000 is applies. This reason is

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Voltage is low

Discharge tube is not coloured

Gas does not conduct current under ordinary pressure

Temperature low

Neutrons was discovered by

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Mosely

Milliken

Chadwick

Ruherford

In the ground state of an atom, the electron is present:

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In the nucleus.

In the second shell.

Nearest to the nucleus.

farthest from the nucleus.

The divisibility of atom was shown by

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Stoney

J.J. Thomson

Millikan

Rutherford

Consider the ground state of Cr atom (Z=24). The numbers of electrons with the azimuthal quantum numbers l = 1 and l = 2 are respectively

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12 and 4

16 and 5

16 and 4

12 and 5

Which of the following is not isoelectronic?

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Na⁺

Mg²⁺

O^2-

Cl^-

The radius of first orbit of H-atom is

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4.75 A°

3.84 A°

8.4 A°

0.529 A°

Effective magnetic moment of Sc³⁺ion is

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1.73

0

5.92

2.83

Energy of electron in first orbit of H atom is

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-45.32 KJ/mole

-82.08 KJ/mole

-52.53 KJ/mole

-1313.31 KJ/mole

Number of neutrons in heavy hydrogen atom is

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0

1

2

3

The ratio of the ionization energy of H and Be³⁺is

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1 : 1

1 : 3

1 : 9

1 : 16

Balmer's series is in ______ region

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Visible

U V

I. R.

None

If the value of principal quantum number is 3. the total possible values for magnetic quantum number will be

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1

4

9

12

The radius of second Bohr's orbit is

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0.053 nm

0.053/4 nm

0.053 x 4 nm

0.053 x 20 nm

Bohr model of atom is contradicted by:

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Planck's quantum theory

Pauli's exclusion theory

Heisenberg's uncertainty principle.

All of above.

The quantum number which describe the orientation of the orbitals is

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Spin quantum number

Principle quantum number

Azimathal quantum number

Magnetic quantum number

Which one of the following statements is true about discovery of neutrons?

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These particles were formed by the bombardment of Alpha-particles on Beryllium.

These particles are formed by the spiting of alpha-particles.

These particles were discovered by natural radioactivity.

None of above.

Which of the following was discovered first:

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Charge to mass ratio of electrons.

Mass of electrons.

Charge of electrons.

All of above at same time.

Rutherford's planetary like picture of the atomic modal was defective because

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It did not describe the quantity of positive charge

It did not explain the repulsion of protons within the nucleus

No empty space between nucleus and the electrons

Moving electron should radiate energy

When the electron jumps form third, fourth, fifth orbits to the second orbit, the transitions are known as

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Paschen

Pfund

Balmer

Brackett

Photons of yellow colour are ______ energetic than violet colour

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More

Less

Equal

None

Which one of the following particles has amass 1/1836 time, that of hydrogen?

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Neutron.

Proton.

Electron.

Positron.

Electrons in degenerate orbitals are placed in separate orbitals with same spin according to

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Hund's rule

Pauli exclusion principle

Aufbau principle

Mosley's law

When 3p orbital is complete, the entering electron goes into

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4s

3d

4p

4f

Electrons arranged in orbitals according to the increasing order of their n + l values, this rule is named as

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Hund's rule

Heisenberg's principle

Paulit exclusion principle

Auf bau principle

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