Nuclei  MCQs

MCQs of Nuclei

Showing 111 to 120 out of 138 Questions
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111.
What percentage of the initial quantity of a radioactive element disintegrates during the mean life time of this element ?
(a) 100%
(b) 50.2%
(c) 90%
(d) 63.2%
Answer:

Option (d)

112.
On which factor the half life of radioactive element is dependent ?
(a) tempeature
(b) pressure
(c) nature of element
(d) amount of radioactive element
Answer:

Option (c)

113.
If a radioactive substance decays for time equal to its mean life, then its fraction that remains undecayed will be _____ .
(a) 63.2
(b) 36.78
(c) 50
(d) 75
Answer:

Option (b)

114.
The activity I of a radioactive element in average life time is _____ .
(a) I0.e
(b) I0e
(c) I02
(d) 2I0
Answer:

Option (b)

115.
For a radioactive element τ = 10 hr. Then its half-life τ12= _____ .
(a) 693 hr
(b) 69.3 hr
(c) 6.93 hr
(d) 0.693 hr
Answer:

Option (c)

116.
If α-particles are incident on one end A of a conductor and β-rays on other end B, then _____ .
(a) the current does not flow in the conductor
(b) a current flows from end A to end B
(c) a current flows from end B to end A
(d) a current flows from both the end towards the mid point of the conductor
Answer:

Option (b)

117.
Which of the following can be help in understanding a nuclear fission ?
(a) Mesons theory for nuclear forces
(b) Proton-proton cyclic process
(c) Single particle model o nucleus
(d) Liquid drop model of nucleus
Answer:

Option (d)

118.
Which of the following substance is not used as moderator ?
(a) graphite
(b) heavy water
(c) Beryllium
(d) liquid sodium metal
Answer:

Option (d)

119.
Which of the following substance is used as a moderator ?
(a) U
(b) D2O
(c) Cd
(d) B
Answer:

Option (b)

120.
Which of the following function is done by the controlled rods ?
(a) They absorb the neutrons
(b) They slow down the neutron
(c) They make neutron fast
(d) They emit neutron
Answer:

Option (a)

Showing 111 to 120 out of 138 Questions
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