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JEE Advanced > Atoms and Nuclei

Explore popular questions from Atoms and Nuclei for JEE Advanced. This collection covers Atoms and Nuclei previous year JEE Advanced questions hand picked by experienced teachers.

Q 1.

Correct4

Incorrect-1

The plate resistance of a triode is {tex} 3 \times 10 ^ { 3 } {/tex} ohms and its mutual conductance is {tex} 1.5 \times 10 ^ { - 3 } {/tex} amp/volt. The amplification factor of the triode is

A

{tex} 5 \times 10 ^ { - 5 } {/tex}

{tex} 4.5 {/tex}

C

{tex} 45 {/tex}

D

{tex} 2 \times 10 ^ { 5 } {/tex}

Explanation

Q 2.

Correct4

Incorrect-1

The half life of radioactive Radon is 3.8 days. The time at the end of which {tex} \frac { 1 } { 20 } {/tex}th of the radon sample will remain undecayed is (given {tex} \log _ { 10 } e{/tex} = 0.4343)

A

3.8 days

16.5 days

C

33 days

D

76 days

Explanation


Q 3.

Correct4

Incorrect-1

An alpha particle of energy {tex} 5\ \mathrm { MeV } {/tex} is scattered through {tex} 180 ^ { \circ } {/tex} by a fixed uranium nucleus. The distance of closest approach is of the order of

A

{tex} 1 {\text{Å}} {/tex}

B

{tex} 10 ^ { - 10 } \mathrm { cm } {/tex}

{tex} 10 ^ { - 12 } \mathrm { cm } {/tex}

D

{tex} 10 ^ { - 15 } \mathrm { cm } {/tex}

Explanation

Q 4.

Correct4

Incorrect-1

Beta rays emitted by a radioactive material are

A

electromagnetic radiations

B

the electrons orbiting around the nucleus

charged particles emitted by the nucleus

D

neutral particles

Explanation

Q 5.

Correct4

Incorrect-1

If elements with principal quantum number {tex} n {/tex} > 4 were not allowed in nature, the number of possible elements would be

60

B

32

C

4

D

64

Explanation

Q 6.

Correct4

Incorrect-1

Consider the spectral line resulting from the transition {tex} n = 2 \rightarrow n = 1 {/tex} in the atoms and ions given below. The shortest wavelength is produced by

A

Hydrogen atom

B

Deuterium atom

C

Singly ionized Helium

Doubly ionised Lithium

Explanation

Q 7.

Correct4

Incorrect-1

The equation {tex} { 4 _ { 1 } ^ { 1 } \mathrm { H } ^ { + } \longrightarrow } _{ 2 } ^ { 4 } \mathrm { He } ^ { 2 + } + 2 \mathrm { e } ^ { - } + 26 \mathrm { MeV } {/tex} represents

A

{tex} \beta {/tex} -decay

B

{tex} \gamma {/tex}-decay

fusion

D

fission

Explanation

Q 8.

Correct4

Incorrect-1

Fast neutrons can easily be slowed down by

A

the use of lead shielding

passing them through water

C

elastic collisions with heavy nuclei

D

applying a strong electric field.

Explanation

Q 9.

Correct4

Incorrect-1

Consider {tex} \alpha {/tex} particles, {tex} \beta {/tex} particles and {tex} \gamma {/tex}-rays, each having an energy of {tex}0.5 \mathrm{MeV}.{/tex} In increasing order of penetrating powers, the radiations are:

{tex} \alpha , \beta , \gamma {/tex}

B

{tex} \alpha , \gamma , \beta {/tex}

C

{tex} \beta , \gamma , \alpha {/tex}

D

{tex} \gamma , \beta , \alpha {/tex}

Explanation

Q 10.

Correct4

Incorrect-1

An energy of 24.6 eV is required to remove one of the electrons from a neutral helium atom. The energy in (eV) required to remove both the electrons from a neutral helium atom is

A

38.2

B

49.2

C

51.8

79.0

Explanation

Q 11.

Correct4

Incorrect-1

A radioactive material decays by simultaneous emission of two particles with respective half-lives 1620 and 810 years. The time, in years, after which one-fourth of the material remains is

1080

B

2430

C

3240

D

4860

Explanation

Q 12.

Correct4

Incorrect-1

A full-wave rectifier circuit along with the output is shown in Figure. The contribution (s) from the diode {tex}1{/tex} is (are)

A

{tex}\mathrm C {/tex}

{tex} \mathrm { A } , \mathrm { C } {/tex}

C

{tex} \mathrm { B , D} {/tex}

D

{tex} \mathrm { A } , \mathrm { B } , \mathrm { C } , \mathrm { D } {/tex}

Explanation

Q 13.

Correct4

Incorrect-1

A particle of mass {tex} M {/tex} at rest decays into two particles of masses {tex} m _ { 1 } {/tex} and {tex} m _ { 2 } , {/tex} having non-zero velocities. The ratio of the de Broglie wavelengths of the particles, {tex} \lambda _ { 1 } / \lambda _ { 2 } , {/tex} is

A

{tex} m _ { 1 } / m _ { 2 } {/tex}

B

{tex} m _ { 2 } / m _ { 1 } {/tex}

{tex}1.0{/tex}

D

{tex} \sqrt { m _ { 2 } } / \sqrt { m _ { 1 } } {/tex}

Explanation

Q 14.

Correct4

Incorrect-1

Which of the following is a correct statement?

Beta rays are same as cathode rays

B

Gamma rays are high energy neutrons

C

Alpha particles are singly ionised helium atoms

D

Protons and neutrons have exactly the same mass

Explanation

Q 15.

Correct4

Incorrect-1

Order of magnitude of density of uranium nucleus is, {tex} \left[ m _ { D } = \right. {/tex} {tex} \left. 1.67 \times 10 ^ { - 27 } \mathrm { kg } \right] {/tex}

A

{tex} 10 ^ { 20 }\ \mathrm { kg } / \mathrm { m } ^ { 3 } {/tex}

{tex} 10 ^ { 17 }\ \mathrm { kg } / \mathrm { m } ^ { 3 } {/tex}

C

{tex} 10 ^ { 14 }\ \mathrm { kg } / \mathrm { m } ^ { 3 } {/tex}

D

{tex} 10 ^ { 11 }\ \mathrm { kg } / \mathrm { m } ^ { 3 } {/tex}

Explanation

Q 16.

Correct4

Incorrect-1

According to Bohr's theory of hydrogen atom, the product of the binding energy of the electron in the {tex} n ^ { \text {th } } {/tex} orbit and its radius in the {tex} n ^ { \text {th } } {/tex} orbit

A

Is proportional to {tex} n ^ { 2 } {/tex}

B

Is inversely proportional to {tex} n ^ { 3 } {/tex}

C

Has a constant value of {tex} 10.2 \mathrm { eV } -{\text{Å}} {/tex}

Has a constant value of {tex}7.2 \mathrm {eV}-{\text{Å}}{/tex}

Explanation

Q 17.

Correct4

Incorrect-1

If an X-ray tube operates at the voltage of {tex} 10 \mathrm { kV } , {/tex} find the ratio of the de Broglie wavelength of the incident electrons to the shortest wavelength of {tex} \mathrm { X } {/tex} -rays produced. The specific charge of electron is {tex} 1.8 \times 10 ^ { 11 } \mathrm { C } \ \mathrm { kg } {/tex}

A

1

0.1

C

1.8

D

1.2

Explanation


Q 18.

Correct4

Incorrect-1

Figure represents some of the lower energy levels of the hydrogen atom in simplified form. If the transition of an electron from {tex} E _ { 4 } {/tex} to {tex} E _ { 2 } {/tex} were associated with the emission of blue light, which one of the following transitions could be associated with the emission of red light?

A

{tex} E _ { 4 } {/tex} to {tex} E _ { 1 } {/tex}

B

{tex} E _ { 3 } {/tex} to {tex} E _ { 1 } {/tex}

{tex} E _ { 3 } {/tex} to {tex} E _ { 2 } {/tex}

D

{tex} E _ { 1 } {/tex} to {tex} E _ { 3 } {/tex}

Explanation

Q 19.

Correct4

Incorrect-1

Which of the following statement is true regarding Bohr's model of hydrogen atom?
(I) Orbiting speed of an electrons decreases as it falls to discrete orbits away from the nucleus
(II) Radii of allowed orbits of electrons are proportional to the principal quantum number
(III) Frequency with which electrons orbit around the nucleus in discrete orbits is inversely proportional to the cube of principal quantum number
(IV) Binding force with which the electron is bound to the nucleus increase as it shifts to outer orbits.
Select the correct answer using the codes given below:

I and II

B

II and IV

C

I, II and III

D

II, III and IV

Explanation

Q 20.

Correct4

Incorrect-1

An electron jumps from the {tex} 4 ^ { \text {th } } {/tex} orbit to the {tex} 2 ^{\mathrm {nd}} {/tex} orbit of hydrogen atom. Given: the Rydberg's constant ={tex} 10 ^ { 5 } \mathrm { cm } ^ { - 1 } . {/tex} The frequency, in {tex} \mathrm { Hz } {/tex}, of the emitted radiation will be

A

{tex} \frac { 3 } { 16 } \times 10 ^ { 5 } {/tex}

B

{tex} \frac { 3 } { 6 } \times 10 ^ { 15 } {/tex}

C

{tex} \frac { 9 } { 16 } \times 10 ^ { 5 } {/tex}

{tex} \frac { 9 } { 16 } \times 10 ^ { 15 } {/tex}

Explanation

Q 21.

Correct4

Incorrect-1

In hydrogen and hydrogen-like atoms, the ratio of {tex} E _ { 4 n } - E _ { 2 n } {/tex} and {tex} E _ { 2 n } - E _ { n } {/tex} varies with atomic number {tex} z {/tex} and principal quantum number {tex} n {/tex} as

A

{tex} \frac { z ^ { 2 } } { n ^ { 2 } } {/tex}

B

{tex} \frac { z ^ { 4 } } { n ^ { 4 } } {/tex}

C

{tex} \frac { Z } { n } {/tex}

None of these

Explanation

Q 22.

Correct4

Incorrect-1

The radius of hydrogen atom in the ground state is {tex} 5.3 \times 10 ^ { - 11 } \mathrm { m } {/tex}. When struck by an electron, its radius is found to be {tex} 21.2 \times 10 ^ { - 11 } \mathrm { m } {/tex}. The principal quantum number of the final state will be

A

1

2

C

3

D

4

Explanation

Q 23.

Correct4

Incorrect-1

The electron in a hydrogen atom makes a transition from {tex} n = n _ { 1 } {/tex} to {tex} n = n _ { 2 } {/tex} state. The time period of the electron in the initial state is eight times that in the final state. The possible values of {tex} n _ { 1 } {/tex} and {tex} n _ { 2 } {/tex} are

{tex} n _ { 1 } = 4 , n _ { 2 } = 2 {/tex}

B

{tex} n _ { 1 } = 8 , n _ { 2 } = 2 {/tex}

C

{tex} n _ { 1 } = 8 , n _ { 2 } = 3 {/tex}

D

{tex} n _ { 1 } = 6 , n _ { 2 } = 2 {/tex}

Explanation

Q 24.

Correct4

Incorrect-1

The speed of electrons in the second orbit of {tex} \mathrm { Be } ^ { 3 + } {/tex} ion will be

A

{tex} \frac { c } { 137 } {/tex}

{tex} \frac { 2 c } { 137 } {/tex}

C

{tex} \frac { 3 c } { 137 } {/tex}

D

{tex} \frac { 4 c } { 137 } {/tex}

Explanation

Q 25.

Correct3

Incorrect-1

The minimum permissible radius of the orbit will be

A

{tex} \frac { 2 \varepsilon _ { 0 } h ^ { 2 } } { m \pi e ^ { 2 } } {/tex}

{tex} \frac { 4 \varepsilon _ { 0 } h ^ { 2 } } { m \pi e ^ { 2 } } {/tex}

C

{tex} \frac { \varepsilon _ { 0 } h ^ { 2 } } { m \pi e ^ { 2 } } {/tex}

D

{tex} \frac { \varepsilon _ { 0 } h ^ { 2 } } { 2 m \pi e ^ { 2 } } {/tex}

Explanation