Question # 1

Gaussian surface is always:

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Rectangular

Spherical

Cylinder

Box shape

Any of these

The range of wavelengths of colurs in the visible colours is

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140 nm to 456 nm

10 nm to 56 nm

410 nm to 656 nm

910 nm to 956 nm

None of these

The minimum wavelength of X-rays produced of 1KV potential difference is applied across the anode and cathode of the tube is

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1.24 x 10^-10m

7.92 x 10^-20m

2.78 x 10^-14m

3.88 x 10^-11m

The natural arrangement of colours in the spectrum of white light spectrum is

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VIBGYOR

ROYBGIV

ROYBIGV

BIGROYV

None of these

Energy required by an electron revolving in certain orbit to jump to an excited state is called:

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Ionization energy

Ionization potential

Excitation energy

Excitation potential

None of these

We can excite an atom by

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Bombardment of particles

Radiating photons

Providing potential difference

All answer are true

In case of braking radiations, when the rate of deceleration is very large, the emitted radiation corresponds to:

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Short wavelength

Large wavelength

Very large wavelenth

Low frequency

Both (B) and (C)

The first series which was identified in the spectrum of hydrogen is called:

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Lyman series

Balmer series

Paschen series

Brackett series

Pfund series

The lasing or active medium in He-Ne laser discharge tube is:

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Nitrogen

Helium

Hydrogen

Neon

None of these

An compared to solid matter, a crack or an air bubble allows:

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Great amount of X-rays to pass

Smallast amount of X-rays to pass

Very samall amount of X-rays to pass

Any of these

None of these

A metastable stae:

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Is an excited state

Is that in which excited electron is stable

Is that in which excited electron is usually unstable

Means a time interval of 10^-8second

Both (A) and (C)

Braking radiation causes:

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Continuous spectrum

Line Spectrum

Band spectrum

Discrete specturm

All of these

The electric field lines start from:

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Positive charge

Negative charge

Either A and B

Neutron

An atom

In helium Neon Laser Neon = 15% and Helium = 85% used. The lasing gas this unit is

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Helium

Neon

Both

None of these

Static electricity is produced by the transfer of:

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Electrons

Protons

One fluid

Two fluid

None of these

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ECAT Physics Chapter 20 Atomic Spectra Online Test MCQs With Answers

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