EASY

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Given below are two statements:
Statement I: Most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus and the electrons revolve around it, is Rutherford's model.
Statement II: An atom is a spherical cloud of positive charges with electrons embedded in it, is a special case of Rutherford's model.
In the light of the above statements, choose the most appropriate from the options given below.

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Important Questions on Atoms

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

Taking the wavelength of first Balmer line in hydrogen spectrum

(n = 3

n = 2)

660 n m

, the wavelength of the

2^{n d}

Balmer line

(n = 4

n = 2)

will be :

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

If the shortest wavelength in Lyman series of hydrogen atom is

A

, then the longest wavelength in Paschen series of

{He}^{+}

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

The first member of the Balmer series of hydrogen atom has a wavelength of

6561 \overset{\circ}{A}

. The wavelength of the second member of the Balmer series (in nm) is_____________

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about

9

. The spectral series are:

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

In Balmer series for hydrogen atom, find the energy of photon corresponding to longest wavelength.

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

For any given series of spectral lines of atomic hydrogen, let $Δ \bar{v} = {\bar{v}}_{m a x} - {\bar{v}}_{m i n}$ be the difference in maximum and minimum wave number in $c m^{- 1}$ .

The ratio $Δ {\bar{v}}_{L y m a n} / Δ {\bar{v}}_{B a l m a r}$ is

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

A donor atom in a semiconductor has a loosely bound electron. The orbit of this electron is considerably affected by the semiconductor material but behaves in many ways like an electron orbiting a hydrogen nucleus. Given that the electron has an effective mass of

0.07 m_{e}

, where

m_{e}

is mass of the free electron and the space in which it moves has a permittivity

13 ε_{0},

then the radius of the electron's lowermost energy orbit will be close to (take, the Bohr radius of the hydrogen atom is

0.53 \overset{°}{A}

)

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

The time period of revolution of electron in its ground state orbit in a hydrogen atom is

1.6 \times 10^{- 16} s .

The frequency of revolution of the electron in its first excited state (in

s^{- 1}

) is:

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

The frequency for a series limit of Balmer and Paschen series respectively are

f_{1}

and

f_{3}

. If the frequency of the first line of Balmer series is

f_{2}

then the relation between

f_{1}, f_{2}

and

f_{3}

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

The graph that depicts Einstein photoelectric effect for a monochromatic source of frequency above the threshold frequency is

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

Calculate the energy in corresponding to light of wavelength

45 n m :

(Planck’s constant

h = 6.63 \times 10^{- 34} J s : s p e e d o f l i g h t c = 3 \times 10^{8} m s^{- 1})

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

A photoelectric surface is illuminated successively by monochromatic light of wavelength

λ

and

\frac{λ}{2}

. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is:
(

h

= Planck's constant,

c

= speed of light)

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

In Balmer series, wavelength of first line is

λ_{1}

and in Brackett series wavelength of first line is

λ_{2}

then

\frac{λ_{1}}{λ_{2}}

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

Given the value of Rydberg constant is

10^{7} m^{- 1}

, the wave number of the last line of the Balmer series in hydrogen spectrum will be:

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

When the electron in hydrogen atom jumps from fourth Bohr orbit to second Bohr orbit, one gets the

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

The shortest wavelength of

H

atom in the Lyman series is

λ_{1}

. The longest wavelength in the Balmer series of

{He}^{+}

is :

HARD

Physics>Modern Physics>Atoms>Bohr Atomic Model

The work function of sodium metal is

4.41 \times 10^{- 19} J .

If photons of wavelength

300 nm

are incident on the metal, the kinetic energy of the ejected electrons will be

(h = 6.63 \times 10^{- 34} J s; c = 3 \times 10^{8} m s^{- 1})

__________

\times 10^{- 21} J

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

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)

EASY

Physics>Modern Physics>Atoms>Bohr Atomic Model

The magnitude of acceleration of the electron in the $n^{th}$ orbit of hydrogen atom is $a_{H}$ and that of singly ionised helium atom is $a_{He}$ . The ratio $a_{H} : a_{He}$ is,

MEDIUM

Physics>Modern Physics>Atoms>Bohr Atomic Model

Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface?

Important Questions on Atoms

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