Classification of Elements and Periodicity in properties- 6

1) The half-life of a radioactive isotope is 2.5 hour. What mass of it remains undecayed after 10 hours? The initial mass of the isotope was 16 g.
a) 32 g
b) 16 g
c) 4g
d) 1g

2) In a nuclear reactor the function of the moderator is
a) To slow down the speed of neutrons
b) To increase the speed of neutrons
c) To produce more neutrons
d) To stop the nuclear reaction

3) Which of the following is used as neutron absorber in the nuclear reactor?
a) Water
b) Deuterium
c) Some compound of uranium
d) Cadmium

4) If the amount of radioactive substance is increased three times, the number of disintegrating atoms per unit time will
a) Be doubled
b) Be tripled
c) become one third
d) be unchanged

5) According to the nuclear reaction 4Be + 42He 126C + 10n, the mass number of the Be atom is:
a) 4
b) 8
c) 6
d) 9

6) A radioactive isotope decays at such a rate that after 96 min. only 1/8th of the original amount remains. The half-life period is
a) 12.0 min
b) 32.0 min
c) 24.0 min
d) 48.0 min

7) Which is the correct statement?
a) Isotopes are always radioactive.
d) gamma rays can be deflected in a magnetic field

8) The half-life of a certain radioactive element is 100 years. The time in which it disintegrates 50% of its mass is:
a) 50 years
b) 200 years
c) 100 years
d) 25 years

9) Which of the following elements belongs to the 4n-series ?
a) Pb-206
b) Bi-209
c) Pb-208
d) Pb-207

10) The change from requires
a) a
b) a
c) a neutron
d) a positron

11) C-14 has a half-life of 5760 years. 100 mg of sample containing C-14 is reduced to 25 mg in:
a) 11520 years
b) 2880 years
c) 1440 years
d) 17280 years

12) An atom bomb is based on the principle of
a) Nuclear fusion
b) Nuclear fission
c) Radioactivity
d) Nuclear fission and fusion both.

13) Which is not fissionable material?
a) U-238
b) U-235
c) U-233
d) Pu-239

14) When a radioactive element emits an electron the daughter element formed will have
a) Mass number of one unit less
b) Atomic number of one unit more
c) Mass number of one unit more
d) Atomic number of one unit less

15) D2O is used in
a) Industry
b) Nuclear reactors
c) Medicine
d) Insecticide

16) A a
a) Positive charge and negligible mass
b) Negative charge and negligible mass
c) Positive charge and some mass
d) Negative charge and some mass

17) emits an, the product has a mass number and atomic number
a) 236, 92
b) 234, 90
c) 238, 90
d) 236, 90

18) The particles more useful for nuclear fission are:
a) Fast neutrons
b) Slow neutrons
c) Fast protons
d) Slow protons

19) Isotopes have the same chemical properties because they have the same
a) Atomic mass
b) Atomic number
c) Mass number
d) Numbers of electrons

20) Which pair represents isobars ?

21) Slow neutrons can cause the fission of

22) Radium with the atomic mass 226 and atomic number 88, on emission of an gives rise to an element whose atomic weight and atomic numbers are
a) 222 and 86
b) 222 and 84
c) 225 and 87
d) 230 and 86

23) belongs to III B group of the periodic table. If it loses one , the new element will belong to the group
a) I B
b) IA
c) III B
d) V B

24) The total binding energy of an is
a) 28.3 MeV
b) 2.83 MeV
c) 20.5 MeV
d) 0.283 MeV

25) The radioactive substances have been decaying and releasing energy as well as radiation on the earth
a) Since the last 2000 years
b) Before the universe was created
c) Since 2 million years
d) Since the formation of earth

26) In which of the following the magic numbers of both protons and neutrons are present?

27) Which particle is used to bombard to give ?
a) Proton
b) Neutron
d) Deutron

28) The quantity of radioactive element, which undergoes 106 disintegrations per second, is called
a) Rutherford
b) Curie
c) Becquerel
d) None

29) The least branching is found in which of the following radioactive series
a) 4n+2
b) 4n
c) 4n+3
d) 4n+l

30) Nuclei with the atomic number or the number of neutrons equal to 2, 8, 28, 50, 82, 126 are more stable. These are called
a) Atomic numbers
b) Magic numbers
c) Mass numbers
d) None

31) The radioactivity of neptunium stops when it is converted to
a) Th
b) Rn
c) Pb
d) Bi

32) Nuclear reactions accompanied by the emission of neutron (s) are

33) Which is the nucleus produced when a 23892U nucleus undergoes a deutron, 2n (d, 2n) reaction followed by a ?

34) The isotope used to find the age of relics is

35) The decay of mass during nuclear fission and fusion are:
a) 0.1%, 0.231%
b) 0.231%, 0.1 %
c) 0.4% and 0.2%
d) 0.3% and 0.6%

36) The half-life period of lead is expected to be
a) 1590 years
b) 1590 days
c) 159 days
d) Zero

37) The hydrogen bomb is based on the principle of
a) Nuclear fission
b) Nuclear fusion
c) Artificial radioactivity
d) Natural radioactivity

38) Positron emission results from the transformation of one nuclear proton into a neutron. The nuclide thus produced will have the
a) Nuclear charge higher by unity
b) Same mass number
c) Increased radioactivity
d) No radioactivity.

39) Which isotope on bombardment with will give ?

40) A magnet will cause the greatest deflection of
a) Gamma rays
b) Beta rays
c) Alpha rays
d) Neutrons

41) The following radiation does not consist of particles of matter:
a) Alpha
b) Beta
c) Gamma
d) Neutrons

42) The waves having the maximum velocity which are produced by radioactive decay are
d) Positron

43) The solar or steller energy emitted by sun and stars is considered to be due to
a) Fission of hydrogen nuclei
b) Fusion of hydrogen nuclei
c) Continuous burning of hydrogen
d) None of these

44) Stable nuclides are those whose N/P ratio is:
a) N/P=1
b) N/P=2
c) N/P > 1
d) N/P < 1

45) What will be the total number of electrons, protons and neutrons in the product formed by loss of one from ?
a) 326
b) 3330
c) 324
d) 332

46) What is the packing fraction of iron? () Atomic mass of Fe = 55.92066.
a) +14.167
b) +73.90
c) -14.167
d) -73.90

47) An element X loses 1— and 2— particles in successive stages. The resulting element would be
a) An isobar of X
b) An isotope of X
c) X itself
d) An isotone of X

48) The half-life of a radioactive element is 30 minutes. One sixteenth of the original quantity of the element will be left after
a) 1 hour
b) 16 hours
c) 4 hours
d) 2 hours

49) The formation of isotopes is due to the
a) Difference of protons
b) Difference of electrons
c) Difference of neutrons
d) None

50) 8.0 g. of a radioactive substance is reduced to 0.5 g. after one hour. The half-life period of the radioactive substance is
a) 15 min
b) 30 min
c) 45 min
d) 10 min

51) The nuclide 24799Es can be obtained by bombarding 23992U in a reactor that emits 5 neutrons. The bombarding particle is

52) The value of the disintegration constant of a radioactive isotope
a) Decreases with increasing temperature
b) Decreases with increasing pressure
c) Increases with increasing concentration
d) Is independent of temperature, pressure, and concentration

53) Which of the following is not radioactive?
a) Cm
b) Ra
c) Mo
d) Md

54) If by mistake some radioactive substance gets into human body, then from the point of view of radiation damage, the most harmful will be one that emits
b) Neutrons

55) Which radioactive isotope is used for temperature control in blood disease?

56) In most stable elements the number of proton and neutron is
a) Even-even
b) Even-odd
c) Odd-even
d) Odd-odd

57) The Segre chart is
a) The variation of B emission vs neutron number (N)
b) The variation of emission vs neutron number (N)
c) The variation of neutron number (N) vs proton number (Z)
d) The variation of positron emission vs neutron number

58) @ 90Th is a member of III group. On losing an , it forms a new element which belongs to
a) I group
b) III group
c) II group
d) IV group

59) What is the symbol for the nucleus remaining after undergoes —emission?

60) The distance between nucleons in an atomic nucleus is of the order of (IF = 10-13cm).
a) 200 Fermi
b) 50 Fermi
c) 2 Fermi
d) 1000 Fermi

61) When the parent nucleus emits a the daughter element is shifted in the periodic table by
a) One place to the right
b) One place to the left
c) Two places to the left
d) Two places to the right

62) The rays whose range in air is very small are
d) Light waves

63) Breeder reactors are nuclear reactors that are capable of converting non-radioactive isotopes into radioactive fissionable isotopes, which can be used to generate energy. 238U is a non- radioactive isotope, it is converted into radioactive

64) An element undergoes followed by two successive The element formed is

65) Radiation emitted by radioactive isotopes can be fatal. They are therefore transported carefully in
a) Metallic bottles
b) Cooled helium
c) Containers made of iron amalgam
d) Containers made of lead

66) Which has therapeutic value?
d) All

67) 128 I has no therapeutic value because
a) It is poisonous
b) It is very stable
c) It decays quickly and loses radioactivity
d) None

68) @ The number of neutrons accompanying the formation of and from the absorption of a slow neutron by followed by nuclear fission is
a) Zero
b) 2
c) 1
d) 3

69) In the radioactive transformation , the nuclei R and Z are ?
a) Isotopes
b) Isobars
c) Isomers
d) Isotones

70) A nucleus is struck by a neutron and changes to along with three neutrons and an unknown product. The unknown product is :

71) When nuclear energy is intended to be harnessed for generation of electricity, potentially destructive neutrons released in a nuclear reactor are absorbed by
a) Heavy water
b) Long rods of Cd
c) Cubic blocks of steel
d) Both (b) and (c)

72) The decay of a radioactive element follows first order kinetics. Hence
b) The rate of decay is independent of the temperature
c) The rate can be altered by changing chemical conditions
d) The element will be completely transformed into a new element after the expiry of two half-life periods.

73) Through the body of every person, millions of particles pass through silently every second. These particles are:
a) Protons
b) Electrons
c) Neutrons
d) None

74) NeutronProton + X + Antineutrino. What is X ?
a) Electron
b) Neutron
c) Proton
d) Deutron

75) Particles having energy of several hundred MeV are called
a) Electrons
b) Nucleons
c) Fast particles
d) Super fast particles

76) The nuclear process that takes place when a hydrogen bomb is exploded is of the same nature as the process taking place
a) In the centre of the earth
b) On the sun and the stars
c) During a red dust storm
d) During atomic bomb fission

77) Which are not emitted by radium?
d) X-rays

78) The radioactive series to which radium, 224Ra belongs is the
a) Uranium series
b) Thorium series
c) Neptunium series
d) Actnium series

79) Neutrons can be detected during the emission of
c) Proton

80) A nuclear reactor may be cooled by transferring the heat generated from the reactor to a turbine steam boiler by using
a) Fe vapours
b) Radioactive carbon
c) Molten sodium
d) Compressed hydrogen

81) The pair of similar radiations from among the following is

82) The strength of nuclear forces when compared to electrostatic forces is

83) All nuclides exhibit radioactivity when the atomic number exceeds
a) 80
b) 90
c) 82
d) 92

84) The formation of a nucleus from its nucleons is accompanied by a/an
a) Decrease in mass
b) Increase in mass
c) No change in mass
d) A decrease or increase or no change in mass

85) The most likely mode of decay for is
d) Electron capture

86) The fundamental particle having the least mass is a/an
a) Meson
b) Neutrino
c) Positron
d) Electron

87) A nuclide emitting gamma rays loses
a) Electrons
b) Electric charge
c) Energy
d) Stability

88) -particles having a velocity almost equal to the velocity of light are called
c) Super fast particles
d) None

89) If two nuclei are fused together in a nuclear reaction, the average energy per nucleon
a) Increases
b) Decreases
c) Remains constant
d) Cannot be determined

90) One atomic mass unit is equal to
d) None

91) In the case of radioactive equilibrium, the one with a higher average life is present in … amount than other with a short average life,
a) Smaller
b) Greater
c) Equal
d) Either

92) Which is the least effective for artificial transmutation ?
a) Neutrons
b) Deutrons
c) Protons

93) An element has a half-life of 5 days. The time taken for 7/8th of a sample to decay is
a) 3.4 days
b) 10 days
c) 15 days
d) 20 days

94) @ In the nuclear change Fission products + neutron + 3.20 x 10-11 J, the energy released when 1 g. of finally undergoes fission is

95) Plutonium decays with t1/2 = 24000 years. If plutonium is stored for 72000 years, the fraction of it remains
a) 1/8
b) 1/3
c) 14
d) 1/2

96) The radioisotope used in the treatment of cancer is
a) C-12
b) Co-60
c) 1-131
d) P-31

97) Which of the following radioactive isotopes is used for hyperthyroidism?

98) In which of the following is radioactive isotope I-131 used ?
a) In the diagnosis of liver and kidney disorder
b) Treatment of thyroid disease
c) To increase the absorption of calcium in the body
d) To locate tumours in the brain

99) The density of nuclear matter is

100) One atom containing 10 protons, 11 neutrons and 10 electrons and another atom containing 11 protons, 10 neutrons and 11 electrons are called?
a) Isotones
b) Isotopes
c) Isobars
d) Isomers


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