PYQSide ExamsMy practice

Nuclei · Question 10

NEET (UG) 2022 (Phase 2)MCQEasy📈 Topic in 25% papers+4−1
1

Given below are two statements In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Statement I is incorrect but statement II is correct
  2. Both statement I and statement II are correct
  3. Both statement I and statement II are incorrect
  4. Statement I is correct but statement II is incorrect

Answer

(3) Both statement I and statement II are incorrect

Solution

Statement I: Law of radioactive decay: dNdt = - N

the rate of decay is directly (not inversely) proportional to the number of nuclei incorrect.

Statement II: the sum of the life times of all nuclei divided by the initial number of nuclei is the mean life = 1 , not the half-life ( T1/2 = 0.693 ) incorrect.

Both statements are incorrect.

Answer: (3)

Out of syllabusNEET (UG) 2022 (Phase 2)

Keep practising — Nuclei

2

At any instant, two elements X1 and X2 have same number of radioactive atoms. If the decay constant of X1 and X2 are 10 and respectively, then the time when the ratio of their atoms becomes 1e respectively will be :

  1. 15
  2. 111
  3. 19
  4. 16
Out of syllabusNEET (UG) 2022 (Phase 2)
3

A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented nuclei is 7.6 MeV while that of fragments is 8.5 MeV. The total gain in the Binding Energy in the process is :

  1. 216 MeV
  2. 0.9 MeV
  3. 9.4 MeV
  4. 804 MeV
NEET (UG) 2021
4

The half life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be :

  1. 23 2
  2. 12
  3. 12 2
  4. 23
Out of syllabusNEET (UG) 2021
5

A radioactive nucleus ZAX Z-1B Z-3C Z-2D, where Z is the atomic number of element X. The possible decay particles in the sequence are :

  1. -, , +
  2. , -, +
  3. , +, -
  4. +, , -
Out of syllabusNEET (UG) 2021
6

The energy equivalent of 0.5 g of a substance is :

  1. 4.5 1013 J
  2. 1.5 1013 J
  3. 0.5 1013 J
  4. 4.5 1016 J
NEET (UG) 2020
7

When a uranium isotope 23592U is bombarded with a neutron, it generates 8936Kr, three neutrons and :

  1. 9140Zr
  2. 10136Kr
  3. 10336Kr
  4. 14456Ba
Out of syllabusNEET (UG) 2020
8

For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is

  1. 20
  2. 10
  3. 30
  4. 15
Out of syllabusNEET 2018
9

Radioactive material 'A' has decay constant '8 ' and material 'B' has decay constant ' '. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that of 'A' will be e ?

  1. 17
  2. 18
  3. 19
  4. 1
Out of syllabusNEET 2017
10

The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is

  1. 15
  2. 30
  3. 45
  4. 60
Out of syllabusNEET 2016 (Phase 2)
11

A nucleus of uranium decays at rest into nuclei of thorium and helium. Then

  1. The helium nucleus has more momentum than the thorium nucleus.
  2. The helium nucleus has less kinetic energy than the thorium nucleus.
  3. The helium nucleus has more kinetic energy than the thorium nucleus.
  4. The helium nucleus has less momentum than the thorium nucleus.
AIPMT 2015

All Nuclei PYQs →

PDFDownload Nuclei PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Physics chapters
Class 11Units and MeasurementsMotion in a Straight LineMotion in a PlaneLaws of MotionWork, Energy and PowerSystem of Particles and Rotational MotionGravitationMechanical Properties of SolidsMechanical Properties of FluidsThermal Properties of MatterThermodynamics (Physics)Kinetic TheoryOscillationsWaves
Class 12Electric Charges and FieldsElectrostatic Potential and CapacitanceCurrent ElectricityMoving Charges and MagnetismMagnetism and MatterElectromagnetic InductionAlternating CurrentElectromagnetic WavesRay Optics and Optical InstrumentsWave OpticsDual Nature of Radiation and MatterAtomsNucleiSemiconductor ElectronicsExperimental Skills (Physics)