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11) Mark the incorrect statement about nuclear fusion?
a) Material used is D2, T3.
b) Percent efficiency is high.
c) It can be controlled.
d) It is not a chain process.
ANSWER : It can be controlled.
12) The speed of a chemical reaction is not affected by:
a) Temperature.
b) Volume.
c) Pressure.
d) Catalyst.
ANSWER : Volume.
13) Find the number of a and ß – particles emitted by 88Ra226
in changing to a stable isotope of 82Pb206.
a) 5, 4
b) 5, 6
c) 6, 8
d) 3, 4
ANSWER : 5, 4
14) The half-life period of 53I125 is 60 days. Find
the percent of the original radioactive present after 180 days.
a) 11%
b) 12.5%
c) 13.5%
d) 10.5%
ANSWER : 12.5%
15) Calculate the percentage activity remaining after 4 years, if the
half-life of cobalt - 60 is 5.26.
a) 50%
b) 45%
c) 59%
d) 49%
ANSWER : 59%
16) Find the rate of disintegration of 0.001g of a sample of Ra226
if half-life period is 1620 years.
a) 4.28 x 10-8 g per year.
b) 4.28 x 10-7 g per year.
c) 3.28 x 10-8 g per year.
d) 3.28 x 10-7 g per year.
ANSWER : 4.28 x 10-7 g per year.
17) Time required for Na24 to lose its activity by 80% is ……………
(half-life = 15 hrs)
a) 36.8 hrs.
b) 32.8 hrs.
c) 34.8 hrs.
d) 33.7 hrs.
ANSWER : 34.8 hrs.
18) Calculate the disintegration constant for a radioactive element which
takes two hours to reduce to half of its initial concentration.
a) 0.3465 hr -1
b) 0.3374 hr -1
c) 0.3221 hr -1
d) 0.323 hr -1
ANSWER : 0.3465 hr -1
19) The half-life period of the element is 1.4 x 1010 years.
Calculate the time in which activity of an element reduces to 90% of its
original value.
a) 2.13 x 109 years.
b) 2.13 x 108 years.
c) 1.13 x 109 years.
d) 1.13 x 108 years.
ANSWER : 2.13 x 109 years.
20) The total charges before and after the reaction is conserved. This
relation is given by:
a) Law of conservation of mass number.
b) Law of conservation of atomic number.
c) Law of conservation of mass and energy.
d) None of these.
ANSWER : Law of conservation of atomic number.
Part 1
Part 2 Part 3 Part 4
Part 5
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