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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What's the size of an electron?

Important Questions on Atoms

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Physics>Modern Physics>Atoms>Early Atomic Models

Any

f

-orbit can accommodate upto

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:

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

Atomic number is represented by:

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

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

EASY

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

HARD

Physics>Modern Physics>Atoms>Early Atomic Models

In a Davisson-Germer experiment, Helium atoms were used in place of electrons. What should be the energy of Helium so that a strong peak of scattered He appears at an angle of

50 °,

as was the case with electrons having an energy of

54 eV ?

(Take mass of

He

atoms to be

7500

times the mass of electrons)

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

The atom is:

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

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

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

The value of magnetic quantum number of the last electron of

" Na "

" is

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

The mass number and the volume of a nucleus is

M

and

V

respectively. If the mass number is increased to

2 M

then the volume is changed to

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

The graph of

\ln (\frac{R}{R_{0}})

versus

\ln A

(

R =

radius of a nucleus and

A =

mass number) is

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:

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

The number of completely filled shells for the element

_{16} S^{32}

MEDIUM

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

On the basis of Thomson's model of an atom, explain how the atom is neutral as a whole.

HARD

Physics>Modern Physics>Atoms>Early Atomic Models

In what way was the Rutherford's atomic model different from that of Thomson's atomic model?

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

In Thomson's mass spectrographs, when an electric field of

2 \times 10^{4} V m^{- 1}

is applied then the deflection produced on the screen is

20 mm

. If the length of the plates is

5 cm

and the distance of the screen from plates is

21 cm

and the velocity of positive ions is

10^{6} m s^{- 1}

, then their specific charge will be:

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

In Thomson mass spectrograph, singly and doubly ionised particles from similar parabola corresponding to magnetic fields of 0.8 T and 1.2 T for a constant electric field. The ratio of masses of ionised particles will be

MEDIUM

Physics>Modern Physics>Atoms>Early Atomic Models

Describe Thomson's model of atom. Why was it rejected?

EASY

Physics>Modern Physics>Atoms>Early Atomic Models

J.J. Thomson's experiment proved the discovery of:

What's the size of an electron?

Important Questions on Atoms

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