IITian Academy - Online Coaching for Foundation Classes , IIT and Medical Entrance Exam.

1. The energy-level diagram for an atom that has four energy states is shown.

What is the number of different wavelengths in the emission spectrum of this atom?

1

3

6

7

2. A graph of the variation of average binding energy per nucleon with nucleon number has a maximum. What is indicated by the region around the maximum?

The position below which radioactive decay cannot occur

The region in which fission is most likely to occur

The position where the most stable nuclides are found

The region in which fusion is most likely to occur

3. A detector, placed close to a radioactive source, detects an activity of 260 Bq. The average background activity at this location is 20 Bq. The radioactive nuclide has a half-life of 9 hours.

What activity is detected after 36 hours?

15 Bq

16 Bq

20 Bq

35 Bq

4. Kindly refer the question below:

The average binding energy per nucleon of the nucleus is 7.5 MeV. What is the total energy required to separate the nucleons of one nucleus of ?

53 MeV

60 MeV

113 MeV

173 MeV

5. The half-life of a radioactive element is 5.0 days. A freshly-prepared sample contains 128 g of this element. After how many days will there be 16 g of this element left behind in the sample?

5.0 days

10 days

15 days

20 days

6. Atomic spectra are caused when a certain particle makes transitions between energy levels.

What is this particle?

Electron

Proton

Neutron

Alpha particle

7. A sample contains an amount of radioactive material with a half-life of 3.5 days. After 2 weeks the fraction of the radioactive material remaining is

94 %.

25 %.

6 %.

0 %.

8. In a nuclear fission reaction, nucleus X splits into nucleus Y and nucleus Z. Which of the following gives a possible order of the nuclei from lowest to highest binding energy per nucleon?

Z → Y → X

Z → X → Y

Y → X → Z

X → Z → Y

9. Kindly refer the question below:

Bismuth-210 is a radioactive isotope that decays as follows.

10. The initial number of atoms in a pure radioactive sample is N. The radioactive half-life of the sample is defined as the

time taken for one atom to undergo decay.

probability for `N/2` atoms to undergo decay.

time taken for `N/2` atoms to undergo decay.

probability that one atom will decay per unit time.

11. Kindly refer the question below:

Which of the following is true about beta minus ( $β^{-}$ ) decay?

An antineutrino is absorbed.

The charge of the daughter nuclide is less than that of the parent nuclide.

An antineutrino is emitted.

The mass number of the daughter nuclide is less than that of the parent nuclide.

12. Geiger and Marsden bombarded a thin gold foil with alpha particles. They observed that a small fraction of the alpha particles were deflected through angles greater than 90˚. What does this observation suggest about the nucleus?

It is at the centre of the atom.

It is surrounded by orbiting electrons.

It is made of protons and neutrons.

It is a small region of the atom and is positively charged.

13. Kindly refer the question below:

The nuclear reaction would best be described as

alpha decay.

nuclear fission.

nuclear fusion.

neutron capture.

14. What is the definition of the unified atomic mass unit?

The mass of one atom of hydrogen.

1/12 of the mass of an atom of carbon -12.

The mass of one atom of carbon-12.

1/16 of the mass of an atom of oxygen -16.

15. Which of the following affects the rate at which a sample of a radioactive material decays?

The mass of the sample

The temperature of the sample

The volume of the sample

The pressure acting on the sample

16. Nucleus P decays by a sequence of emissions to form nucleus Q.

One $α$ particle and two β⁻ particles are emitted during the sequence. Which statement is correct?

Nucleus P has the same number of neutrons as nucleus Q.

Nucleus P is an isotope of nucleus Q.

Nucleus P has a greater charge than nucleus Q.

Nucleus P has fewer protons than nucleus Q.

17. Kindly refer the question below:

Which of the following correctly identifies the three particles emitted in the decay of the nucleus into a nucleus of

`α, β^−, γ`

`β^−, γ,barnu`

`α, γ,barnu`

`α, β−, narnu`

18. Kindly refer the question below:

The rest mass of a proton is $938 MeV c^{- 2}$ . The energy of a proton at rest is

$9.38 J$

$9.38 \times 10^{8} \times (3 \times 10^{8})^{2} J$

$9.38 \times 10^{8} eV$

$9.38 \times 10^{8} \times (3 \times 10^{8})^{2} eV$

19. A simple model of the hydrogen atom suggests that the electron orbits the proton. What is the force that keeps the electron in orbit?

Electrostatic

Gravitational

Strong nuclear

Centripetal

20. The Geiger–Marsden experiment provides evidence for

the existence of discrete atomic energy levels.

the existence of the neutron.

a dense positively charged nucleus.

the stability of some nuclei.

21. Emission and absorption spectra provide evidence for

the nuclear model of the atom.

natural radioactivity.

the existence of isotopes.

the existence of atomic energy levels.

22. Data concerning nuclides are plotted using the axes below.

What are the axis labels for this graph?

23. What is the relationship between nucleon number A, proton number Z and neutron number N?

A=Z=N

A+Z=N

A−Z=N

Z−A=N

24. The nuclear reaction

is an example of

nuclear fission.

radioactive decay.

nuclear fusion.

artificial transmutation.

25. A radioactive isotope has a half-life of two minutes. A sample contains sixteen grams of the isotope. How much time elapses until one gram of the isotope remains?

6 minutes

8 minutes

10 minutes

12 minutes

26. Kindly refer the question below:

When an alpha particle collides with a nucleus of nitrogen-14 a nucleus X can be produced together with a proton. What is X?

27. Kindly refer the question below:

The binding energy per nucleon of What is the energy required to separate the nucleons of this nucleus?

24 MeV

42 MeV

66 MeV

90 MeV

28. Which of the following is true in respect of both the Coulomb interaction and the strong interaction between nucleons in an atom?

29. Kindly refer the question below:

A radioactive sample has activity A₀ at t=0. What will be the activity of the sample after two half-lives?

zero

`A_0/4`

less than `A_0/4` if the sample is kept at high pressure

greater than `A_0/4` if the sample is kept at high temperature

30. Kindly refer the question below:

Element X decays through a series of alpha (α) and beta minus (β^–) emissions. Which series of emissions results in an isotope of X?

1α and 2β^–

1α and 4β^–

2α and 2β^–

2α and 3β^–

31. Kindly refer the question below:

Which Feynman diagram shows beta-plus (β⁺) decay?

32. A radio-isotope has an activity of 400 Bq and a half-life of 8 days. After 32 days the activity of the sample is

200 Bq.

100 Bq.

50 Bq.

25 Bq.

33. As quarks separate from each other within a hadron, the interaction between them becomes larger. What is the nature of this interaction?

Electrostatic

Gravitational

Strong nuclear

Weak nuclear

34. Three of the fundamental forces between particles are

I. strong nuclear

II. weak nuclear

III. electromagnetic.

What forces are experienced by an electron?

I and II only

I and III only

II and III only

I, II and III

35. Which of the following lists three fundamental forces in increasing order of strength?

electromagnetic, gravity, strong nuclear

weak nuclear, gravity, strong nuclear

gravity, weak nuclear, electromagnetic

electromagnetic, strong nuclear, gravity

36. The relationship between proton number Z, neutron number N and nucleon number A is

$A = Z - N$ .

$Z = A + N$ .

$N = A - Z$ .

$N = A + Z$ .

37. Kindly refer the question below:

The mass defect for deuterium is 4×10^–30kg. What is the binding energy of deuterium?

4×10^–7eV

8×10^–2eV

2×10⁶eV

2×10¹²eV

38. What is the energy equivalent to the mass of one proton?

9.38 × (3 × 10⁸)² × 10⁶ J

9.38 × (3 × 10⁸)² × 1.6 × 10^–19 J

`(9.38×10^8)/(1.6×10^−19)J`

9.38 × 10⁸ × 1.6 × 10^–19 J

39. A simple model of an atom has five energy levels. What is the maximum number of different frequencies in the emission spectrum of that atom?

4

6

10

25

40. In the Geiger–Marsden experiment α-particles are scattered by gold nuclei. The experimental results provide evidence that

$α$ -particles have discrete amounts of kinetic energy.

most of the mass and positive charge of an atom is concentrated in a small volume.

the nucleus contains protons and neutrons.

gold atoms have a high binding energy per nucleon.

41. Kindly refer the question below:

The binding energy per nucleon of a nucleus is 3 MeV. What is the minimum energy needed to
completely separate the nucleons of .

12 MeV

9 MeV

6 MeV

3 MeV

42. Two pure samples of radioactive nuclides X and Y have the same initial number of atoms.

The half-life of X is $T_{\frac{1}{2}}$ After a time equal to 4 half-lives of X the ratio

What is the half-life of Y?

${`0.25T_(1/2).`}$

${`0.5T_(1/2).`}$

${`3T_(1/2).`}$

${`4T_(1/2).`}$

43. Kindly refer the question below:

The number of neutrons and the number of protons in a nucleus of an atom of the isotope of uranium are

44. What is the definition of the unified atomic mass unit?

`1/12` the mass of a neutral atom of carbon-12

The mass of a neutral atom of hydrogen-1

`1/12` the mass of a nucleus of carbon-12

The mass of a nucleus of hydrogen-1

45. Which particle is acted on by both the strong nuclear force and the Coulomb force?

Antineutrino

Electron

Neutron

Proton