Ch 13. Nuclei Flashcards
X-rays are
Electromagnetic waves
The nucleus of any atom is made up of
Proton And Neutron
The unit of radioactivity is
Curie
Which of the following has the highest penetrating power?
y-rays (gamma rays)
The half life of a radioactive isotope (²¹⁰Bi) is 5 days. The fraction of the nuclei undecayed at the end of 20 days will be
1/16
The function of moderator in nuclear reactor is to
Slow the speed of neutrons
Which of the following represents the α-decay of
AZ X (A ke neeche Z aur X)
z X A ———– z-2 Y A-4 + ₂He⁴
z neeche, A oopar, z-2 neeche, A-4 oopar,
Which of the following is not a fundamental particle?
α-particle
The source of solar energy is
Nuclear fission
The least stable nucleus is
₂He⁴
Atomic number decrease with the emission of α-particles from the nucleus by
2
Cathode rays are
Electrons
Density of nucleus is about
2.29 × 10¹⁷ kg m⁻³
Which of the relations is correct for radioactive atom?
Half life = 0.6931 average life
β-rays are fast moving
Electrons
1 amu is equal to
1.6 × 10⁻²⁷ kg
γ-rays are similar to
X-rays
Which of the following is correct for radioactive element?
T a = 1/λ
Neeche a
Which of the following is not charged?
Photon
The atomic number and mass number for a specimen are Z and A respectively. The number of neutrons in the atom will be
A - Z
The quantities, which remain conserved in a nuclear reaction
Total charge, Angular momentum, Linear momentum
Ans - All of the above
Which one of the following is charge less?
Photon particle
Time during which the amount of radioactive substance becomes half of its initial amount is called
Half life
β-rays are deflected in
Both magnetic and electric field
Which one of the following has maximum penetrating power?
γ-rays
The number of neutrons in an atom of ₉₀Th²³⁰ is
140
Statement 1st : All nuclei are not a same size.
Statement 2nd : The size of nucleus depends on atomic mass.
Both the statements are true and statement 2nd is the correct explanation of statement 1st
The relation between half-life time T₁/₂ and decay constant is
T₁/₂ = 0.693/λ
Which of the following is correct for α-particle?
Helium nucleus
Which of the following equations is correct?
²³⁸ U —- ²³⁴ Th + ⁴ He
⁹² ⁹⁰ ²
Which of the following relations is correct for mass and energy?
mc² = E
Statement 1st : Energy is released in nuclear fusion.
Statement 2nd : Total binding energy of the product is less than total binding energy of reactants in nuclear reaction for nuclear fusion.
Both the statements are true and statement 2nd is the correct explanation of statement 1st
