12th class important MCQs on nuclear energy

 

 

1) Which of the following is the correct expression for the mass number A? (N = number of neutrons, Z = atomic number):-

A) A = Z + N
B)A = Z - N
C)A = Z × N
D) A = Z² - N

ANSWER=A) A = Z + N
Explain:-

 

2) What is the value of 1 atomic mass unit equal to? :-

A) (1/12) × mass of oxygen atom
B)(1/12) × C¹² mass of the atom
C)(1/12) × mass of nitrogen atom
D) (1/12) × mass of He⁴ atom

ANSWER=B)(1/12) × C¹² mass of the atom
Explain:-

 

3) In Einstein's principle E = mc², what is the value of c?:-

A) 2 × 10⁸ m/s
B)332 m/s
C)3 × 10⁸ m/s
D) 776 ×10⁴ m/s

ANSWER=C)3 × 10⁸ m/s 
Explain:-

 

4) How much energy will we get by converting 1U mass into energy?:-

A) 1000 MeV
B)746 MeV
C)540 MeV
D) 931 MeV

ANSWER=D) 931 MeV
Explain:-

 

5) How much energy will we get from the decay of m mass?:-

A) m × 931 MeV
B)m² × 931 MeV
C)m³ × 931 MeV
D) None of these

ANSWER=A) m × 931 MeV
Explain:-

 

6) 1U mass is equal to how many kg? :-

A) 1.96 × 10⁻²⁷ kg
B)2.67 × 10⁻³¹ kg
C)1.6 × 10⁻²⁷ kg
D) 1.67 × 10⁻²⁸ kg

ANSWER=C)1.6 × 10⁻²⁷ kg
Explain:-

 

7) Mass of 1 electron from 1U:-

A) is equal to
B)It is less.
C)is higher.
D)Different electrons can have more or less mass than1U.

ANSWER=B)It is less.
Explain:-

 

8) What is the mass of 1 proton?:-

A) 3.1 × 10⁻³¹ kg
B)1.67 × 10⁻²⁸ kg
C)1.67 × 10⁻³¹ kg
D)1.67 × 10⁻²⁷ kg

ANSWER=D)1.67 × 10⁻²⁷ kg
Explain:-

 

9) What is the total charge on 1 electron? :-

A)1.602 × 10⁻¹⁹ coulomb
B)1.67 × 10⁻²⁷ coulomb
C)1.67 × 10⁻³¹ coulomb
D)1.602 × 10⁻²⁸ coulomb

ANSWER=A)1.602 × 10⁻¹⁹ coulomb
Explain:-

 

10) On which two fundamental particles does the mass of an atom mainly depend? :-

A)proton and electron
B)neutron and electron
C)neutrons and protons
D)None of these.

ANSWER=C)neutrons and protons
Explain:-

 

11) The atomic number of nitrogen is 7. What is the total coulomb charge on one nucleus of nitrogen? :-

A)1.67 × 10⁻²⁷ × 7 coulombs
B)1.602 × 10⁻¹⁹ × 7 coulombs
C)1.602 × 10⁻¹⁸ × 7 coulombs
D)7 × 10⁻¹⁹ coulomb

ANSWER=B)1.602 × 10⁻¹⁹ × 7 coulombs
Explain:-

 

12) In which unit is the atomic radius usually measured? :-

A)Fermi
B)mm
C)cm
D)m

ANSWER=A)Fermi
Explain:-

 

13) The value of radius r of a nucleus is:-

A)r = R₀A²
B)r = R₀√A
C)r = R₀A⅓
D)r = R₀A³

ANSWER=C) R₀A⅓
Explain:-

 

14) How many meters are there in 1 fermi? :-

A)10⁻¹⁰ m
B)10⁻⁹ m
C)10⁻⁸ m
D)10⁻¹⁵ m

ANSWER=D)10⁻¹⁵ m
Explain:-

 

15) What is a mass defect? ​:-

A)total mass loss of protons
B)the sum total of the masses of all the particles in the nucleus - the mass of the nucleus
C)loss of mass of neutrons
D)the sum of the masses of all the particles in the nucleus + the mass of the nucleus

ANSWER=B)the sum total of the masses of all the particles in the nucleus - the mass of the nucleus
Explain:-

 

16) What is the binding energy concerning the nucleus?:-

A)The nucleus's total energy  required to hold the electrons together.
B)The amount of energy that can take electrons out of the atom.
C)the total energy required to break the nucleus into its particles.
D)the amount of energy required to eject neutrons from the nucleus.

ANSWER=C) The total energy required to break the nucleus into its particles.
Explain:-

 

17) Which of the following represents the binding energy?:-

A)m/C
B)m + C²
C)m.C²
D)C²/Δm

ANSWER=C) m.C²
Explain:-

 

18) If the mass of the _ZH^A nucleus is M, then which of the following shows mass decay?

A)m = [ Zmₚ + (A - Z)mₙ - M ]
B)m = [ Zmₚ - (A - Z) mₙ - M ]
C)m = [ Zmₚ + (A + Z) mₙ - M ]
D)m = [ Zmₚ + (A - Z)mₙ + M ]

ANSWER=A)m = [ Zmₚ + (A - Z)mₙ - M ]
Explain:-

 

19) The symbol of a Neutron is given by:-

A) ₀n²
B)2n²
C)₀n¹
D)₀n⁰

ANSWER=C)₀n¹
Explain:-

 

20) Which of the following is the formula of the proton? :-

A)₀H¹
B)₁H¹
C)₁H²
D)₁H³

ANSWER=B)₁H¹
Explain:-

 

21) Which of the following rays does not have any charge?:-

A)𝛄-rays
B)⍺-rays
C)β-rays
D)none of the above.

ANSWER=A)𝛄-rays
Explain:-

 

22) Which of the following rays has the highest penetrating power?:-

A)𝛄-rays
B)⍺-rays
C)β-rays
D) each one has the same penetrating power.

ANSWER=A)𝛄-rays
Explain:-

 

23) Which of the following rays are not deflected in electric and magnetic fields?:-

A)𝛄-rays
B)⍺-rays
C)β-rays
D)none of the above.

ANSWER=A)𝛄-rays
Explain:-

 

24) Which of the following rays has the highest ionizing power?:-

A)𝛄-rays
B)⍺-rays
C)β-rays
D)infrared radiation

ANSWER= B)⍺-rays
Explain:-

 

25) Which of the following ray has zero mass? :-

A)𝛄-rays
B)⍺-rays
C)β-rays
D)infrared radiation

ANSWER= A)𝛄-rays
Explain:-

 

26) The velocity of which of the following rays is equal to the velocity of light?:-

A)𝛄-rays
B)⍺-rays
C)β-rays
D)infrared radiation

ANSWER= A)𝛄-rays
Explain:-

 

27) In nature, some substances continuously decay spontaneously, releasing special types of radiation. This event is called:-

A) Nuclear Fusion
B) nuclear fission
C) Carbon emissions
D) Radioactivity

ANSWER= D)Radioactivity
Explain:-

 

28) Who discovered radioactivity? :-

A) Rutherford
B) Becquerel
C) Chadwick
D) Curie

ANSWER= B)Becquerel
Explain:-

 

29)What is half-life? :-

A) Half of the time taken for the complete disintegration of the radioactive substance.
B) the time taken to disintegrate half the atoms of the radioactive substance.
C) Half of the average lifespan of a radioactive substance.
D) twice the average life of a radioactive substance.

ANSWER= B)the time taken to disintegrate half the atoms of the radioactive substance.
Explain:-

 

30)The value of half-life is:-

A) T = λ × 0.693
B) T = λ/0.693
C) T = λ - 0.693
D) T = 0.693/λ

ANSWER= D)T = 0.693/λ
Explain:-

 

31)What is the relation between half-life and the average age of radioactive material?:-

A) Half age = λ × Average age
B) Half age = 0.693/average age
C) Half age = 0.693 × Average age
D) Half age = Average age / 0.693

ANSWER= C)Half age = 0.693 × Average age
Explain:-

 

32)In which unit is radioactivity measured? :-

A) Curie
B) Fermi
C) Angstrom
D) Becquerel

ANSWER= A)Curie
Explain:-

 

33)What is used as a moderator in a nuclear reactor? :-

A) Cadmium
B) Carbon
C) water
D) heavy water

ANSWER= D) heavy water
Explain:-

 

34)Which of the following is the formula for heavy water?:-

A) H₂O
B) 2H₂O
C) D₂O
D) D₃O

ANSWER= C) D₂O
Explain:-

 

35)In which country was the first hydrogen bomb detonated in 1952?:-

A) Russia
B) France
C) Germany
D) United States of America

ANSWER= D)United States of America
Explain:-

 

36) The number of atoms left after a time t in a radioactivity event will be:-

A) N = N₀e^t
B) N = N₀λ^et
C) N = N₀e⁻^λt
D) N = N₀e^λt

ANSWER= C)N = N₀e⁻^λt
Explain:-

 

37) On which principle is the hydrogen bomb based? :-

A) nuclear fission
B) nuclear fusion
C) chemical reaction
D) radioactivity

ANSWER= B) nuclear fusion
Explain:-

 

38) Penetration power of alpha particle than that of beta particle:-

A) is less.
B) is higher.
C) is equal to
D) is much more.

ANSWER= A) is less.
Explain:-

 

39) Which is the lightest among alpha, proton, and neutron?:-

A) Alpha
B) Proton
C) Neutron
D) All have equal mass.

ANSWER= B) Proton
Explain:-

 

40)The ₈O¹⁶ nucleus is collided with the deuteron. Alpha particles are emitted in this process. The nuclei formed in this process will be:-

A) ₇N¹³
B) ₅B¹⁰
C) ₇N¹⁴
D) ₆C¹²

ANSWER= C) ₇N¹⁴
Explain:-

 

41) Which of the following radioactive material is used to find the age of fossil materials?:-

A) radioactive nitrogen
B) ₅B¹⁰
C) ₆C¹⁴
D) ₆C¹²

ANSWER= C) ₆C¹⁴
Explain:-

 

42) Which of the following deflect in an electric field?:-

A) ultraviolet radiation
B) Gamma rays
C) X- rays
D) cathode rays

ANSWER= D) cathode rays
Explain:-

 

43)Which of the following is indivisible?:-

A) Atom
B) nucleus
C) proton
D) photons

ANSWER= D) photons
Explain:-

 

44) Magnetic field can be used to detect the presence of which of the following?:-

A) alpha and gamma rays
B) alpha, gamma and beta rays
C) alpha and beta rays
D) beta and gamma rays

ANSWER= C) alpha and beta rays
Explain:-

 

45) Beta rays produced during radioactivity are made up of:-

A) electrons
B) positron
C) photons
D) proton

ANSWER= A) electrons
Explain:-

 

46) Average age of radioactive substance is:-

A) less than half-life.
B) are more than half-life.
C) equal to half-life.
D) ⅓ × half life.

ANSWER= B) are more than half-life.
Explain:-