Multiple Choice Questions On Nuclei With Answers pdf
There is only a short time left for the exam. In such a situation, you must revise the important topic Class 12 Physics Chapter 13 Nuclei NEET Questions. Here are Experts who are telling Nuclei NEET MCQs are the most important in NEET. Which ones you should take a look at and start your Class 12 Nuclei MCQ Pdf Preparation.
MCQs On Nuclei class 12 NEET
1. The half-life period of radioactive material if its activity drops to (1/16)th of its initial value in 30 years is________
(a) 1.5 years
(b) 3.5 years
(c) 7.5 years
(d) 15 years
2. In a sample of a radioactive substance, what percentage decays in one mean lifetime?
(a) 70 %
(b) 63.2 %
(c) 45.8 %
3. Which is the necessary and sufficient condition for an element to element to be naturally radioactive?
(a) Z > 50
(b) Z > 60
(c) Z > 70
(d) Z > 83
4. During the lifetime of a radioactive element as time passes the number of its nuclei decreases and along with that_____
(a) Activity and λ go on decreasing
(b) Activity and λ go on increasing
(c) Activity decrease but λ remains constant
(d) Activity decreases but λ increases
5. Half-life of a radioactive element is 5 min. At the end of 20 min. Its_____% quantity will remain undisintegrated.
6. The various series of the hydrogen spectrum, which of the following lies wholly in the ultraviolet region?
(a) Balmer Series
(b) Paschen Series
(c) Brackett series
(d) Lyman Series
7. What is the energy needed to ionize the H-atom from its second excited state if the energy of the ground state of the H-atom is 13.6 eV?
(a) 3.4 eV
(b) 1.51 eV
(c) 12.1 eV
(d) 13.6 eV
8. Which of the following is a correct statement?
(a) Equal fractions disintegrate in equal intervals of time.
(b) The rate of disintegration is directly proportional to the number of atoms present in the sample at that instant.
(c) A radioactive sample takes an infinite time to disintegrate completely
(d) All of the above
9. How many numbers of spectral lines are observed when hydrogen atoms are excited from the ground state to the state of principal quantum number 4?
10. The quantity which is not conserved in a nuclear reaction is__________
(d) none of these.
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11. A radioactive nucleus emits a beta particle. The parent and daughter nuclei are________
12. The mass number of iron nucleus is 56 the nuclear density is____________
(a) 2.29 × 10¹⁶ kg m-³
(b) 2.29 × 10¹⁷ kg m-³
(c) 2.29 × 10¹⁷ kg m-³
(d) 2.29 × 10¹⁵ kg m-³
13. The radius of a spherical nucleus as measured by electron scattering is 3.6 FM. What is the mass number of the nucleus most likely to be?
14. The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an
(a) isomer of parent
(b) isotone of parent
(c) isotope of parent
(d) isobar of parent
15. An electron emitted in beta radiation originates from________
(a) inner orbits of an atom
(b) free electrons existing in the nuclei
(c) decay of a neutron in a nuclei
(d) photon escaping from the nucleus
16. Two elementary particles which have almost infinite life are________
(a) electron and neutron
(b) neutron and proton
(c) electron and proton
(d) none of the above
17. Out of 6c¹⁴, 7N¹³, 7N¹⁴ and 8O¹⁸, the pair of isotones is__________
(a) 6C¹⁴, 8O¹⁶
(b) 7N¹⁴, 7N¹³
(c) 7N¹⁴, 6C¹⁴
(d) 7N¹⁴, 8O¹⁶
18. In gamma rays emission from a nucleus,
(a) only the proton number changes
(b) both the proton number and neutron number change
(c) there is no change in the proton number and neutron number
(d) only the neutron number changes
19. Which word equation represents β+ decay?
(a) proton → neutron + electron + electron antineutrino
(b) proton → neutron + positron + electron antineutrino
(c) proton → neutron + positron + electron antineutrino
(d) proton → neutron + positron + electron neutrino
20. The radius of a nucleus is__________
(a) directly proportional to its mass number
(b) inversely proportional to its atomic weight
(c) directly proportional to the cube root of its mass number
(d) None of these
21. The electrons cannot exist inside the nucleus because________
(a) the de-Broglie wavelength associated with the electron in β -decay is much less than the size of the nucleus
(b) the de-Broglie wavelength associated with the electron in β -decay is much greater than the size of the nucleus
(c) the de-Broglie wavelength associated with the electron in β -decay is equal to the size of the nucleus
(d) the negative charge cannot exist in the nucleus
22. When the number of nucleons in nuclei increases, the binding energy per nucleon
(a) increases continuously with the mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) first increases and then decreases with the increase of the mass number
23. The radius of a spherical nucleus as measured by electron scattering is 3.6 FM. What is the mass number of the nucleus most likely to be?
24. During negative β-decay, an antineutrino is also emitted along with the emitted electron. Then,
(a) only linear momentum will be conserved
(b) total linear momentum and total angular momentum but not total energy will be conserved
(c) total linear momentum, and total energy but not total angular momentum will be conserved
(d) total linear momentum, total angular momentum, and total energy will be conserved
25. In nuclear reaction, there is conservation of_________
(a) mass only
(b) energy only
(c) momentum only
(d) mass, energy, and momentum