Q.1

The time required for half of the __________ of a radioactive isotope to decay is called its half life.

  • nuclei
  • electrons
  • protons
  • neutrons
Q.2

__________ have the same mass number, but different nuclear charge.

  • Isotopes
  • Isobars
  • Isotones
  • none of these
Q.3

Pick out the wrong statement.

  • The ratio of the density of the 'nucleus' to that of the 'atom' is 1012 .
  • α-particle is identical with a doubly charged helium ion.
  • The mass of deuterium atom is half that of helium atom.
  • Gamma rays are high energy electrons.
Q.4

The disintegration rate of a radioactive element

  • progressively increases.
  • progressively decreases.
  • remains constant throughout.
  • may increase or decrease depending on the material.
Q.5

U-content in enriched uranium, that is normally used in power reactors (e.g., at Tarapur atomic power plant), is about __________ percent.

  • 85
  • 50
  • 3
  • 97
Q.6

Bhabha Atomic Research Centre (BARC) located at Trombay (near Bombay) has

  • five operating research reactors (namely Apsara, Cirus Zerelina, Purnima and Dhurva).
  • a 420 MW nuclear power plant.
  • a very large capacity (100 tons/yr) heavy water plant.
  • all (a), (b) and (c).
Q.7

The electric power generation cost in nuclear power plant is less than that in a coal based thermal power plant, mainly because the

  • fuel cost per unit power generated is less.
  • thermal efficiency of the former is higher.
  • maintenance cost of the former is less.
  • none of these.
Q.8

Heavy water used in the nuclear reactors to slow down the speed of neutrons is

  • highly purified water.
  • a compound of oxygen and deuterium.
  • water having dissolved salts of heavy metals.
  • none of these.
Q.9

Function of control rod in a nuclear reactor is to control

  • temperature
  • pressure
  • fuel consumption
  • absorption of neutrons
Q.10

The ratio of neutrons to protons of an element having a mass number and atomic number ofandrespectively is

  • 1
  • 0.5
  • 2
  • 4
Q.11

Heavy water (D2O) in a nuclear reactor serves as a

  • coolant
  • moderator
  • both (a) & (b)
  • neutron absorber
Q.12

A fast breeder reactor employs

  • graphite as moderator.
  • water as coolant.
  • molten sodium as coolant as well as moderator.
  • U-235 as fuel.
Q.13

Which of the following types of nuclear reactors is most prone to radioactive hazards ?

  • Pressurised water reactor
  • Gas cooled reactor
  • Molten sodium cooled reactor
  • Boiling water reactor
Q.14

Thermal nuclear reactors using enriched uranium as fuel contains a maximum of __________ percent fissile material i.e. U-235.

  • 1
  • 2
  • 3
  • 7
Q.15

Nuclear fuel generally used in reactors is uranium oxide instead of uranium, because the former has higher

  • melting point, hence can be subjected to higher temperature.
  • density ; hence core volume for a given power output would be smaller.
  • resistance to effects of irradiation.
  • all (a), (b) and (c).
Q.16

A fertile material is the one, which can be

  • converted into fissile material on absorption of neutron.
  • fissioned by slow (thermal) neutrons.
  • fissioned by fast neutrons.
  • fissioned by either slow or fast neutrons.
Q.17

Pick out the wrong statement.

  • The nucleus of a hydrogen atom is identical with a proton.
  • A, β-ray particle is identical with an electron.
  • Mass of an electron is about 1/1800th of the lightest nucleus.
  • Positron is heavier than a proton.
Q.18

If 4 gm of a radioisotope has a half life period ofdays, the half life of 2 gm of the same istotope will be __________ days.

  • 5
  • 10
  • 20
  • 30
Q.19

The 92U238 emits an a-particle. The product is

  • 90U234
  • 90U238
  • 90U236
  • 92U236
Q.20

Graphite is used in nuclear reactor as

  • insulation lining of the reactor.
  • fuel.
  • lubricant.
  • retarder of neutron velocity.
Q.21

Which of the following ores contains maximum percentage of uranium ?

  • Carnotite
  • Thorium.
  • Rescolite
  • Pitchblende
Q.22

The ratio of atomic radius to its nuclear radius is about

  • 105
  • 108
  • 1012
  • 1015
Q.23

Which one is different for the neutral atoms of the isotopes of an element ?

  • Atomic weights
  • Atomic numbers
  • Number of protons
  • Number of electrons
Q.24

Which one is radioactive in nature ?

  • Helium
  • Deuterium
  • Heavy hydrogen
  • Tritium
Q.25

The atomic weight and atomic number of an element are A and Z respectively. What is the number of neutrons in the atom of that element ?

  • A+Z
  • A- Z
  • A
  • Z
Q.26

Nuclear fuel complex, Hyderabad is engaged in the job of

  • manufacture of nuclear fuel elements/assemblies .
  • processing of uranium ore.
  • treatment of spent fuel.
  • none of these.
Q.27

Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of __________ percent of U-(i.e. fissile material).

  • 15
  • 45
  • 65
  • 85
Q.28

Thorium metal

  • resembles steel in appearance.
  • is less hard (in the range of silver).
  • is highly ductile.
  • all (a), (b) and (c).
Q.29

__________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.

  • Molten sodium cooled
  • Helium cooled
  • Boiling water
  • Pressurised water
Q.30

Uranium ore is currently mined & concentrated at

  • Jadugoda
  • Ghatsila
  • Khetri
  • Alwaye
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