Nuclei  MCQs

MCQs of Nuclei

Showing 31 to 40 out of 138 Questions
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31.
The final product of a natural radioactive series is _____ .
(a) Pb
(b) U
(c) Th
(d) Rn
Answer:

Option (a)

32.
The activity of a radioactive sample _____ .
(a) can be increased by heating it
(b) can be increased by cooling it
(c) cannot be increased by any method
(d) can be increased by reducing agent
Answer:

Option (c)

33.
The maximum energy of electrons, obtained by β-decay, is known as _____ .
(a) zero-point energy
(b) end-point energy
(c) ionization energy
(d) fermi energy
Answer:

Option (b)

34.
The decay constant of a stable end product in a radioactive series is _____ .
(a) 0
(b) ∞
(c) small
(d) large
Answer:

Option (a)

35.
Which of the following cannot be emitted by radioactive substances during their decay ?
(a) Electrons
(b) Protons
(c) Neutrinos
(d) Helium nuclei
Answer:

Option (b)

36.
A neutron decays into _____ .
(a) one proton, one neutron and one γ
(b) one β+ and one v
(c) one proton, one β- and one v
(d) one proton, one β+ and one v
Answer:

Option (c)

37.
Which spectrum is continuous _____ .
(a) α-rays
(b) β-rays
(c) γ-rays
(d) All of the above
Answer:

Option (b)

38.
The half-life of a radio-isotope is 4 h. If initial mass of the isotope was 200 g, then mass remaining after 24 h will be _____ .
(a) 1.042 g
(b) 2.084 g
(c) 3.125 g
(d) 4.167 g
Answer:

Option (c)

39.
A radioactive sample at any instant has its disintegration rate 5000 dpm. After 5 min, the rate is 1250 dpm. The decay constant per minute is _____ .
(a) 0.8 ln 2
(b) 0.4 ln 2
(c) 0.2 ln 2
(d) 0.1 ln 2
Answer:

Option (b)

40.
Two identical radioactive nuclides are prepared in identical situations and then kept in identical surroundings. The half-life of nuclides is 6 × 103 days. Both the nuclides get decayed in _____ .
(a) 6 × 103days
(b) greater than or less than 6 × 103 days but takes the same time
(c) cannot be predicted
(d) None of the above
Answer:

Option (c)

Showing 31 to 40 out of 138 Questions
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