Nuclear physics-part (2)

Total Questions: 45

21. Hydrogen bomb is based on the principle of- [U.P.P.C.S. (PRE) 2010 67th B.P.S.C. (PRE) 2022]

(a) Controlled fusion reaction
(b) Uncontrolled fusion reaction
(c) Controlled fission reaction
(d) Uncontrolled fission reaction

Correct Answer: (b) Uncontrolled fusion reaction

Solution:Hydrogen bomb's enormous explosive power results from an uncontrolled, self-sustaining chain reaction in which isotopes of hydrogen (deuterium and tritium) combined under extremely high temperature and pressure to form helium in a process known as nuclear fusion.

22. Hydrogen bomb was developed by : [U.P.P.C.S.(MAINS) 2015]

(a) Edward teller
(b) Bernor Bon Bron
(c) J.Robert Oppenheimer
(d) Samual Cohen

Correct Answer: (a) Edward teller

Solution:Edward Teller, one of the most famous scientists of 20th century was known as "father of hydrogen bomb". He was born in January, 1908 in Hungary; In November, 1952 the United States conducted its first nuclear test of a fusion bomb or'hydrogen bomb' at Eniwetok in Marshall Island.

23. The ultimate product of radioactive disintegration of uranium is- [Chhattisgarh P.C.S (PRE) 2013]

(a) Lead
(b) Radium
(c)Thorium
(d) Plutonium
(e) Uranium

Correct Answer: (a) Lead

Solution:Uranium is the first in a long chain of radioactive elements that decay until the stable element lead is formed.

Uranium undergoes a series of radioactive decays, transforming through various intermediate radioactive isotopes of elements like thorium, radium, and others. These decays continue until a stable, non-radioactive isotope is formed. In the case of the most common naturally occurring isotope of uranium, Uranium-238 (²³⁸ $U$ ), the stable end product of this decay series is Lead-206 (²⁰⁶ $P b$ ).

24. Consider the following statements: [I.A.S. (PRE) 2001]

In a nuclear reactor, self-sustained chain reaction is possible, because:

1.More neutrons are released in each of the fission reactions.

2. The neutrons immediately take part in the fission process.

3. The fast neutrons are slowed down by graphite.

4. Every neutron released in the fission reaction initiates further fission.

Which of these statement are correct?

(a) 1,2 and 3
(b) 1 and 3
(c) 2 and 4
(d) 2,3 and 4

Correct Answer: (b) 1 and 3

Solution:Nuclear reactor, formerly known as atomic pile (Atomic furnace) uses Uranium-235 or Plutonium-239 as fuel. When this fissile atomic nucleus absorbs a neutron, it may undergo nuclear fission. The heavy nucleus splits into two or more lighter nuclei, releasing kinetic energy, gamma radiation, and free neutrons. To reduce the speed of neutrons in this reaction H₂O( light water), D₂O (Heavy water),graphite or beryllium oxide are used as the moderator. This whole process is called self-sustained chain reaction, so statement 1 and 3 are correct.

25. What is a Nuclear Reactor? [U.P.P.C.S. (PRE) 1992]

(a) Place where atomic bomb is built.
(b) Heavy water pond.
(c) The emitter furnace.
(d) Atomic furnace.

Correct Answer: (d) Atomic furnace.

Solution:A nuclear reactor is a device that controls a nuclear chain reaction, producing heat through the process of fission, similar to how a furnace produces heat.

26. Which statement is not associated with nuclear fission: [Uttarakhand P.C.S. (PRE) 2016]

(a) Neutron- induced nuclear reaction.
(b) Energy generation in stars.
(c) Source of energy in nuclear reactor that produces electricity.
(d) Enormous energy is released in an atom bomb.

Correct Answer: (b) Energy generation in stars.

Solution:Nuclear fission is a type of reaction in which a heavy atomic nucleus splits into fragments of roughly equal mass releasing huge amount of energy. In contrast, nuclear fusion occurs when two or more smaller atoms fuse together to form a heavier atom releasing large amount of energy. Neutron induced nuclear reaction, nuclear reactors producing electricity and atom bomb are based on the nuclear fission reactions. whereas energy generation in stars is due to nuclear fusion.

27. Consider the following statements about nuclear fusion reactors: [U.P.R.O/A.R.O. (PRE) 2016]

1. They work on the principle of fission of heavy nuclei.

2. They usually have Tokamak design.

3. They operate at very high temperature of these.

(a) Only i and iii are correct
(b) Only i and ii are correct
(c) Only ii and iii are correct
(d) All the three i, ii and iii are correct

Correct Answer: (c) Only ii and iii are correct

Solution:Nuclear fusion reactions work on the principle of fusion of two light nuclei. So, statement (i) is incorrect. Nuclear fusion reactions are also called'Thermonuclear reaction' because they operate at very high temperature. Usually, nuclear fusion reactors have Tokamak design.

28. The difference between nuclear reactor and atom bomb is that : [U.P.P.C.S. (PRE) 1999 I.A.S. (PRE) 1995]

(a) There is no chain reaction in nuclear reactor whereas this happens in atom bomb.
(b) The chain reaction in nuclear reactor is controlled.
(c) The chain reaction in nuclear reactor in not controlled.
(d) Atom bomb is based on nuclear fusion whereas in nuclear reactor, nuclear fission occurs.

Correct Answer: (b) The chain reaction in nuclear reactor is controlled.

Solution:The chain reaction process used in nuclear reactors and atom bombs both release vast amount of energy, but the manner in which the energy is controlled and utilized is different in both the cases. In nuclear reactors, the reaction is moderated and controlled for peaceful purpose, while in nuclear bombs the reaction is uncontrolled and used for destruction.

29. Which one of the following pairs is not correctly matched: [U.P.U.D.A/L.D.A. (Pre) 2002 U.P. P.C.S. (Pre) 2001, 2003]

(a) Discovery of Meson - Hideki Yukawa

(b) Discovery of Positron - C.D. Anderson and U.F. Hess

(d) Synthesis of transuranic elements - Enrico Fermi

Correct Answer: (d)

Solution:In 1935 Meson particles were discovered by Japanese physicist Hideki Yukawa. Positron, the antiparticle or the antimatter counterpart of the electron was discovered by C.D. Anderson and U.F. Hess in 1932. In 1938, Hans Albrecht Bethe described the nuclear reactions that give power to the sun and other stars. In synthesis of transuranic elements, Glenn T. Seaborg played an important role instead of Enrico Fermi. The fact is that he attempted to prepare a transuranic element in 1934 in Rome but failed to do so.

30. Read the following statements- [U.P. P.C.S. (Pre) 1994]

Statement (A): Ernest Rutherford said in Royal Society that a man will never be able to get nuclear energy.

Reason (R): He was confident that the Law of Einstein will fail and the volume will not be converted to energy.

(a) Both (A) and (R) are true and (A) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is correct but (R) is not correct.
d) (R) is correct but (A) is not correct.

Correct Answer: (a) Both (A) and (R) are true and (A) is the correct explanation of (A).

Solution:According to question both statement and reason are correct and reason (R) is the correct explanation of statement (A).

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Nuclear physics-part (2)