Q.1

The radioisotope used to study the thyroid gland is

  • iodine
  • cobalt
  • iron
  • carbon
Q.2

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.3

A fast breeder reactor

  • utilises fast neutrons for causing fission.
  • converts fertile material (e.g., U-238) into fissile material (Pu-239).
  • normally employs molten sodium as coolant.
  • all (a), (b) and (c).
Q.4

Coolant used in a fast breeder reactor is

  • molten sodium
  • heavy water
  • ordinary water
  • helium
Q.5

Percentage of U-in natural uranium is around

  • 0.71
  • 99.29
  • 0.015
  • 29.71
Q.6

A moderator __________ the neutrons.

  • slows down
  • absorbs
  • accelerates
  • reflects
Q.7

Nuclides having the same atomic numbers are termed as

  • isotopes
  • isomers
  • isotones
  • isobars
Q.8

Use of molten metal as a coolant in fast breeder reactor helps in

  • rapid heat transfer from the core.
  • accelerating the reaction rate in the core.
  • breeding neutrons.
  • accelerating the neutrons.
Q.9

The function of moderators in nuclear reactor is to

  • slow down the secondary neutrons.
  • absorb the secondary neutrons.
  • control the chain reaction.
  • none of these.
Q.10

Thermal shield is used in high powered nuclear reactors to

  • protect the walls of the reactor from radiation damage.
  • absorb the fast neutrons.
  • slow down the secondary neutrons.
  • protect the fuel element from coming in contact with the coolant.
Q.11

Enrichment of uranium is done to increase the concentration of __________ in the natural uranium.

  • U-238
  • U-233
  • U-235
  • Pu-239
Q.12

Which is a fertile nuclear fuel ?

  • U-233
  • U-235
  • Pu-239
  • Th-232
Q.13

The half life period of a radioactive element depends on its

  • temperature
  • pressure
  • amount
  • none of these
Q.14

The main ore of thorium is

  • pitchblende
  • monazite sand
  • limonite
  • galena
Q.15

The ratio of mass of a neutron to that of an electron is aboutWhat is the ratio of the mass of a proton to that of an electron?

  • 159
  • 1837
  • 2537
  • 10000
Q.16

First experimental observation of nuclear fission was done by

  • Plane
  • Rutherford
  • Fermi
  • Hahn and Strassman
Q.17

Pressure of CO2 gas (which is a coolant) in the Calder-Hall nuclear reactor is __________ kgf/cm2 .

  • 0.2
  • 7
  • 35
  • 50
Q.18

The main ore of uranium is

  • pitchblende
  • monazite sand
  • cassiterite
  • chalcopyrite
Q.19

A radioactive isotope undergoes decay with respect to time following __________ law.

  • logarithmic
  • exponential
  • linear
  • inverse square
Q.20

Atoms of U-and U-differ in structure by three

  • electrons and three protons
  • protons
  • neutrons
  • electrons
Q.21

Primary purpose of a __________ nuclear reactor is to supply a high neutron flux of the order of 1013 to 1014 neutrons/cm2 second.

  • research
  • power
  • breeder
  • homogeneous
Q.22

In the gaseous diffusion process of uranium enrichment, the natural uranium is converted into gaseous

  • uranium oxide
  • uranium hexaflouride
  • uranium carbide
  • uranium sulphate
Q.23

Fuel for a nuclear reactor (thermal) is

  • uranium
  • plutonium
  • radium
  • none of these
Q.24

Thermal neutrons which are used to cause the fission of U-have energy __________ eV.

  • < 0.025
  • > 1
  • 1-25
  • > 200.
Q.25

Thorium can be converted into U-in a __________ reactor.

  • liquid metal cooled
  • fast breeder
  • thermal
  • swimming pool
Q.26

The number of neutrons accompanying the formation of 54Xe139 and 38Sr94 from the absorption of a slow neutron by 92U235 , followed by nuclear fission is

  • 1
  • 2
  • 3
  • 4
Q.27

What is the average life of a radioactive atom having a 'half life period' of T ?

  • 1.44 T
  • 0.144 T
  • 14.4 T
  • 2T
Q.28

Specific gravity of uranium and plutonium is about

  • 9
  • 13
  • 19
  • 27
Q.29

The half life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half life period of a radioactive substance is one month, then

  • 3/4th of it will disintegrate in two months.
  • it will completely disintegrate in two months.
  • it will completely disintegrate in four months.
  • l/8th of it will remain intact at the end of four months.
Q.30

Atoms with same number of neutrons, but different number of nucleons are called

  • isotones
  • isobars
  • isotopes
  • isoters
0 h : 0 m : 1 s