Question # 1

Which is not characteristic of Laser.

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Monochromatic

Coherent

Intense

Multi direction

Life time of metastable states is

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10^-6 sec or more

10^-3 sec or more

10^-5 sec or more

None of these

An electron in H -atom is excited from ground state n=4 , How many spectral lines are possible in this case.

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6

5

4

3

_____ has the largest de Broglie wavelength at same speed.

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Proton

Alpha particle

Carbon atom

Electron

Photons emitted in inner shell transition are.

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Continuous X -rays

Discontinuous X rays

Characteristic X rays

Energetic X rays

Helium-Neon laser discharge tube contains neon

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82%

15%

25%

85%

An atom can reside in excited state for

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10^-8 second

One second

10^-10 second

More than one second

Which is not true for X rays

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X rays are not defected by electric field

X rays are polarized

X rays consist of electromagnetic waves

X rays can be diffracted by grating

Balmer series lies in

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Visible region

Invisible region

Ultraviolet region

Infrared region

If 13.6 eV energy is required to ionize the hydrogen atom, then the required energy to remove an electron from n=2 is:

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10.2 eV

0 eV

3.4 eV

6.8 eV

When meta I is heated sufficiently electrons are given off by the metal. This phenomenon is known as.

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Photoelectric effect

Piezo electric effect

Thermionic emission

Secondary emission

Radius of first orbit of an atom is r1= 0.053 nm, Radius of second orbit r2 will be.

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0.106 nm

0.212 nm

0.053 nm

0.53 x 10^-10 nm

Laser can be made by creating.

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Meta stable

Population inversion

Excited state

All of these

First spectral series of hydrogen atom was discovered by

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Lyman

Rydberg

Balmer

Paschen

The series in infrared region is:

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Paschen series

Bracket series

Pfund series

All of above

The value of Rydberg constant is

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1.0974 x 10⁷ m^-1

1.0974 x 10^-7 m^-1

1.0974 x 10⁶ m^-1

1.0974 x 10^-6 m^-1

The radius of 10th orbit in hydrogen atom is.

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0.053 nm

0.53 nm

5.3 nm

53 nm

The velocity of electron moving is 1st orbit of hydrogen atom is:

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2.09 x 10⁶ ms^-1

2.18 x10⁶ ms^-1

2.19 x 10⁶ ms^-1

3.18 x10⁶ ms^-1

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