Question # 1

Ultraviolet region lies in ______ series

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Layman

Balmer

P fund

B racket

Atoms of hydrogen gas can be excited by passing electric current through it when the gas is filled into the discharge tube at a pressure which is

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Less than atmospheric pressure

Much less than atmospheric pressure

Greater than atmospheric pressure

Much greater than atmospheric pressure

Both C and D

If the distance between two charges is doubled,the force between them will become:

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Double

Half

One third

One fourth

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

Tick the series which lie/s in. the infra-red region.

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Pfund series

Brackett series

Paschen series

All of these

None of these

Gaussian surface is always:

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Rectangular

Spherical

Cylinder

Box shape

Any 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

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)

Photons must have energy equal to

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ev

En

hf

None of these

The photocopying process is called:

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Geography

Sonography

Xerography

Zerography

None of these

Laser is a beam of:

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Visible light

Infra red light

Ultra violet light

Violet light only

yellow light only

The process of formation of spectrum is called:

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Interference

Spectroscopy

Dispersion

Reflection

Botha (A) and (D)

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

The holes created in the L and M shells are occupied by transitions of:

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Electrons from lower states

Electrons from higher state

Positrons from higher states

Electrons from K shell

Both (A) and (B)

X-rays produced in a tube operating at 10⁵V. The speed of X-rays produced is

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3 x 10⁸m/s

3.1 x 10⁸m/s

2.8 x 10⁸m/s

1.88 x 10⁸m/s

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