Nuclear physics-part (2)

Total Questions: 45

1. Which one of the is not correct : [U.P.P.C.S.(pre) 1999]

(a) Theory of evolution was propounded by Charles Darwin.
(b) The breaking apart of the nucleus of an atom is called fusion.
(c) 'Dry ice' is nothing but solid carbon dioxide.
(d) Telephone was invented by Graham Bell.

Correct Answer: (b) The breaking apart of the nucleus of an atom is called fusion.

Solution:Option (B) is not correct. It is because the breaking apart of the nucleus of an atom is called fission not fusion. Fission is a process in which the heavy nucleus of an atom splits into smaller parts.

2. One of these particles is claimed to have invited which rebut the Einstein's theory of relativity : [U.P.P.S.C.(pre)2009]

(a) Microwave photon
(b) Neutrino
(c) Liquid Crystal
(d) Light emitting diode

Correct Answer: (a) Microwave photon

Solution:The two physicists Gunter Nimtz Alfons Stahlhofen of the University of Koblenz, Germany claimed that they had propelled microwave photons faster than the speed of light. This would be the direct violation of a key content of Einstein's special theory of relativity that states that nothing under any circumstance can exceed the speed of light.

3. Cyclotrons are used to accelerate : [U.P.P.C.S. (pre) 1997]

(a) Neutrons
(b) Protons
(c) Atoms
(d) Ions

Correct Answer: (b) Protons

Solution:Cyclotron is a machine used to accelerate charged particle such as alpha particles, deuteron, proton etc. up to a very high speed.

4. Which one of the following can be used to confirm whether drinking water contains a gamma emitting isotope or not? [I.A.S.(PRE) 1995]

(a) Microscope
(b) Lead plate
(c) Scintillation counter
(d) Spectrophotometer

Correct Answer: (c) Scintillation counter

Solution:Scintillation counter: A scintillation counter is a radiation detector that works by converting the energy of incident radiation (like gamma rays) into light pulses (scintillations). These light pulses are then detected and measured, allowing for the detection and quantification of gamma radiation. This is the correct instrument for confirming the presence of a gamma-emitting isotope.

5. The energy of sun is released due to : [42th B.P.S.C. (Pre) 1997 R.A.S/R.T.S. (PRE) 1993]

(a) Nuclear fission
(b) Nuclear fusion
(c) Oxidation reactions
(d) Reduction Reactions

Correct Answer: (b) Nuclear fusion

Solution:The sun produce energy by the nuclear fusion in its core. Since there is a huge amount of hydrogen in the core. these atoms stick together and fuse into a helium atom. This energy is then radiated out from the core and moves across the solar system. This is the main source of energy for the sun and stars. Besides that the gravitational contraction in stars is also the source of their energy.

6. Stars obtains their energy from : [U.P.P.C.S.(pre) 2000]

1. Nuclear fusion

2. Gravitational contraction

3. Chemical reaction

4. Nuclear fission

Select your answer from the codes given below :

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

Correct Answer: (a) 1 and 2

Solution:

•Nuclear fusion: This is the primary energy source of stars during their main sequence and later stages. In the core of stars, lighter atomic nuclei (mainly hydrogen) fuse together to form heavier nuclei (like helium), releasing tremendous amounts of energy in the process according to Einstein's famous equation, $E = m c²$ .

•Gravitational contraction: During the early stages of a star's formation, gravitational contraction plays a significant role in heating the core to temperatures high enough to initiate nuclear fusion. However, once stable nuclear fusion begins, it becomes the dominant energy source, counteracting further gravitational collapse. Gravitational contraction can become important again in the later stages of a star's life when nuclear fuel is exhausted.

7. The stars receive their energy from which of the following? [Uttarakhand P.C.S. (PRE) 2006]

(a) Nuclear fusion
(b) Nuclear fission
(c) Chemical reaction
(d) Gravitational pull

Correct Answer: (a) Nuclear fusion

Solution:The sun produce energy produces by the nuclear fusion in its core. Since there is a huge amount of hydrogen in the core. these atoms stick together and fuse into a helium atom. This energy is then radiated out from the core and moves across the solar system. This is the main source of energy for the sun and stars. Besides that the gravitational contraction in stars is also the source of their energy.

8. Which one of the following is the source of renewable energy in stars? [U.P.P.C.S. (PRE) 2009]

(a) Hydrogen changes into helium.
(b) Helium changes into hydrogen.
(c) Decay of radioactive material.
(d) Excess of oxygen which is helpful in burning and generate energy.

Correct Answer: (a) Hydrogen changes into helium.

Solution:(Hydrogen to Helium): Stars, during their main sequence phase (which is the longest part of their lives), primarily generate energy through the nuclear fusion of hydrogen nuclei into helium nuclei in their cores. This process is continuous and converts a small amount of mass into a tremendous amount of energy (

E = m c²

). As long as there is a sufficient supply of hydrogen in the star's core, this fusion process will continue, making it a relatively "renewable" source over the star's lifespan, which can be billions of year

9. The source of energy from the Sun is : [Uttrakhand U.D.A./L.D.A.(MAINS) 2006]

(a) Nuclear fission
(b) Nuclear fusion
(c) Photoelectric effect
(d) Cherenkov effect

Correct Answer: (b) Nuclear fusion

10. The important nuclear fuel available in India in abundance is : [U.P.Lower Sub. (pre) 2003 R.A.S/R.T.S (PRE) 1992]

(a) Uranium
(b) Thorium
(c) Iridium
(d) Plutonium

Correct Answer: (b) Thorium

Solution:India is one country that has an abundance of an important nuclear fuel thorium. According to the Department of Atomic energy, the resource estimates of monazite sands along its coastal regions, particularly in Kerala and Odisha. ( principal source of thorium in India) are at 12.73 million tonnes in 2020.

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Nuclear physics-part (2)