Match List ‐ I (Experiment performed) with List ‐ II (Phenomena discovered/associated)and select the correct option from the options given below the lists List-I List-II ( a ) Davisson and Germer experiment i Wave nature of electrons b Millikan's oil drop experiment ii Charge of an electron c Rutherford experiment iii Quantisation of energy levels d Franck-Hertz experiment ( iv ) Existence of the nucleus

( a ) ‐ ( i ) , ( b ) ‐ ( ii ) , ( c ) ‐ ( iv ) , ( d ) ‐ ( iii )

( a ) ‐ ( iii ) , ( b ) ‐ ( iv ) , ( c ) ‐ ( i ) , ( d ) ‐ ( ii )

( a ) ‐ ( iv ) , ( b ) ‐ ( iii ) , ( c ) ‐ ( ii ) , ( d ) ‐ ( i )

( a ) ‐ ( i ) , ( b ) ‐ ( ii ) , ( c ) ‐ ( iii ) , ( d ) ‐ ( iv )

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G.P. Thomson experimentally confirmed the existence of matter waves by the phenomena of

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Important Questions on Atoms

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Physics>Modern Physics>Atoms>Early Atomic Models

Match List $‐ I$ (Experiment performed) with List $‐ II$ (Phenomena discovered/associated)and select the correct option from the options given below the lists

	List-I		List-II
$(a)$	Davisson and Germer experiment	$(i)$	Wave nature of electrons
$(b)$	Millikan's oil drop experiment	$(ii)$	Charge of an electron
$(c)$	Rutherford experiment	$(iii)$	Quantisation of energy levels
$(d)$	Franck-Hertz experiment	$(iv)$	Existence of the nucleus

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Physics>Modern Physics>Atoms>Early Atomic Models

In 1911, the physical Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property which led Rutherford to use gold was that it was

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

In Thomson's experiment for the determination of $(\frac{e}{m})$ of electron, electric field of intensity $' E'$ only is applied. Now the deflection produced by the electron beam is directly proportional to:

HARD

Physics>Modern Physics>Atoms>Early Atomic Models

Consider a hydrogen-like ionized atom with atomic number

Z

with a single electron. In the emission spectrum of this atom, the photon emitted in the

n = 2 t o n = 1

transition has energy

74.8 eV

higher than the photon emitted in the

n = 3 t o n = 2

transition. Given that the ionization energy of the hydrogen atom is

13.6 eV

, what is the value of

Z

HARD

Physics>Modern Physics>Atoms>Early Atomic Models

Consider the following statement:

(I) All isotopes of elements have the same number of neutrons.

(II) Only one isotope of an element can be stable and non-radioactive.

(III) All elements have isotopes.

(IV) All isotopes of Carbon can form chemical compounds with Oxygen $- 16$ .

The correct option regarding an isotope is:

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

In a Frank - Hertz experiment, an electron of energy

5 .6 eV

passes through mercury vapour and emerges with an energy

0 .7 eV .

The minimum wavelength of photons emitted by mercury atoms is close to:

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Physics>Modern Physics>Atoms>Early Atomic Models

Any

f

-orbit can accommodate upto

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Physics>Modern Physics>Atoms>Early Atomic Models

Both the nucleus and the atom of some element are in their respective first excited states. They get de-excited by emitting photons of wavelengths

λ_{N}, λ_{A}

respectively. The ratio

\frac{λ_{N}}{λ_{A}}

is closest to:

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Physics>Modern Physics>Atoms>Early Atomic Models

Electrons behave like gas in J.J. Thompson experiment because they

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Physics>Modern Physics>Atoms>Early Atomic Models

The atom is:

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Physics>Modern Physics>Atoms>Early Atomic Models

In a hydrogen like atom electron makes transition from an energy level with quantum number

n

to another with quantum number

(n - 1)

. If

n >> 1

, the frequency of radiation emitted is proportional to :

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

The pair of atoms among the following having the same structure is

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Physics>Modern Physics>Atoms>Early Atomic Models

Consider third orbit of ${He}^{+}$ (helium), using non-relativistic approach, the speed of electron in this orbit will be given constant $K {=9×10}^{9}$ , $Z =2$ and $h$ (Planck's Constant) $= 6 .6 \times 10^{- 34} J s$

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Physics>Modern Physics>Atoms>Early Atomic Models

As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

If an electron in a hydrogen atom jumps from the third orbit to the second orbit, it emits a photon of wavelength

λ

. When it jumps from the fourth orbit to the third orbit, the corresponding wavelength of the photon will be

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

According to Bohr's theory, the time averaged magnetic field at the centre (i.e., nucleus) of a hydrogen atom due to the motion of electrons in the

n^{t h}

orbit is proportional to: (

n =

principal quantum number)

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

An electron in a hydrogen atom jumps from second Bohr orbit to ground state and the energy difference of the two states is radiated in the form of photons. These are then allowed to fall on a metal surface having a work-function equal to

4.2 eV

, then the stopping potential is [Energy of electron in

n^{th}

orbit

= - \frac{13 .6}{n^{2}} eV

]

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Physics>Modern Physics>Atoms>Early Atomic Models

Atomic number is represented by:

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Physics>Modern Physics>Atoms>Early Atomic Models

The value of magnetic quantum number of the last electron of

" Na "

" is

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Physics>Modern Physics>Atoms>Early Atomic Models

The number of completely filled shells for the element

_{16} S^{32}

G.P. Thomson experimentally confirmed the existence of matter waves by the phenomena of

Important Questions on Atoms

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