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If first excitation potential of a hydrogen like atom is $V$ electron volt, then the ionization energy of this atom will be:

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Important Questions on Modern Physics - I

HARD

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IMPORTANT

Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 2

All electrons ejected from a surface by incident light of wavelength

200 nm

can be stopped before travelling

1 m

in the direction of uniform electric field of

4 N C^{- 1}

. The work function of the surface is:

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 3

An electron of mass

' m',

when accelerated through a potential

V

has de-Broglie wavelength

λ .

The de-Broglie wavelength associated with a proton of mass

M

accelerated through the same potential difference will be:

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 4

Two hydrogen atoms are in excited state with electrons residing in

n = 2 .

First one is moving towards left and emits a photon of energy

E_{1}

towards right. Second one is moving towards right with same speed and emits a photon of energy

E_{2}

towards right. Taking recoil of nucleus into account during emission process

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 5

In a hydrogen atom following the Bohr's postulates the product of linear momentum and angular momentum is proportional to

(n)^{x}

where

' n'

is the orbit number. Then

' x'

is:

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 7

The wavelengths of

K_{α} x -

rays of two metals

' A'

and

' B'

are

\frac{4}{1875 R}

and

\frac{1}{675 R}

respectively, where

R

is Rydberg's constant. The number of elements lying between

' A'

and

' B'

according to their atomic numbers is

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 8

One of the lines in the emission spectrum of

L i^{2 +}

has the same wavelength as that of the

2^{nd}

line of Balmer series in hydrogen spectrum. The electronic transition corresponding to this line is:

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 9

If the short wavelength limit of the continuous spectrum coming out of a Coolidge tube is

10 \overset{°}{A},

then the de-Broglie wavelength of the electrons reaching the target metal in the Coolidge tube is approximately:

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Practice Book for KVPY Aptitude Test - Stream SX Physics>Chapter 11 - Modern Physics - I>Exercise#1>Q 10

The photon radiated from hydrogen corresponding to

2^{nd}

line of Lyman series is absorbed by a hydrogen like atom

' X'

2^{nd}

excited state. As a result the hydrogen like atom

' X'

makes a transition to

n^{th}

orbit. Then,

If first excitation potential of a hydrogen like atom is V electron volt, then the ionization energy of this atom will be:

Important Questions on Modern Physics - I

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If first excitation potential of a hydrogen like atom is $V$ electron volt, then the ionization energy of this atom will be: