A moderator _____________ the neutrons?

Related Mcqs:

1. Thermal neutrons which are used to cause the fission of U-235 have energy _____________ eV?

   A. < 0.025
   B. > 1
   C. 1-25
   D. > 200

2. Neutrons have mass approximately equal to that of _____________ atoms?

   A. Hydrogen
   B. Helium
   C. Deuterium
   D. None of these

3. Out of the following, nucleus of _____________ atom contains the largest number of neutrons?

   A. U-235
   B. U-238
   C. U-239
   D. Pu-239

4. A heterogeneous reactor is the one, in which the moderator and the________________?

   A. Coolant are different materials
   B. Coolant are present in different phases (e.g., heavy water and graphite)
   C. Fuel are present in different phases (e.g. uranium and heavy water)
   D. None of these

5. Which of the following may not need a moderator ?

   A. Candu reactor
   B. Fast breeder reactor
   C. Homogeneous reactor
   D. Pressurised water reactor

6. Ordinary water is not used as a moderator because, it___________________?

   A. Has a low absorption cross-section
   B. Has a low scattering cross-section
   C. Absorbs neutrons
   D. Does not absorb neutrons

7. ____________ moderator is used in a fast breeder reactor?

   A. Graphite
   B. Heavy water
   C. Beryllium
   D. No

8. Which of the following is not used as a moderator in nuclear reactor ?

   A. Molten sodium
   B. Light water
   C. Beryllium
   D. Boron hydride

9. Heavy water is used as a moderator in a _____________________?

   A. Pressurised water reactor (PWR)
   B. Boiling water reactor (BWR)
   C. Candu reactor
   D. Molten sodium cooled reactor

10. Atoms with same number of neutrons, but different number of nucleons are called___________________?

    A. Isotones
    B. Isobars
    C. Isotopes
    D. Isostere