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This MCQ is based on the Nuclei The Centre Of the Atom which includes the Radius of the Nucleus, Mass Defect, Packing Fraction, Nature of Nuclear Force, Radioactivity, and many more.
A radioactive isotope has a half-life of T years. The time it takes its activity to reduce to 3.125% is
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:
A nuclear explosive is designed to deliver 1 MW power in the form of heat energy. If the explosion is designed with nuclear fuel consisting of U235 to run a reactor at this power level for one year, then the amount of fuel needed is (given energy per fission is 200 MeV)
When one gm of mass is converted into energy, it is equal to:
The mass no. of a nucleus is M and its atomic no. is Z. The number of neutrons in the nucleus is :
Energy of electron in the 1st orbit of H-atom is:
The more readily fissionable isotope of uranium has an atomic mass of:
Alpha particle emitted from a radioactive material are:
The ground state energy of Hydrogen atom is -13.6 eV. What is the potential energy of electron in this state?
What will happen in a time of 7 hours, if a radioactive substance has an average life of 7 hours?
What is the half-time of a radioactive sample (in minutes), if its mean life is 200 s?
Which will be the unknown nucleus formed when 22Ne10 decays into two α-particles and an unknown nucleus?
A 300-day old radioactive substance shows an activity of 5000 dps, 150 days later its activity becomes 2500 dps. What was its initial activity?
Find the probability that the nucleus of 87Ra221 undergoes decay after three half-lives if it’s a radioactive substance that has a half-life of 6 days.
The Bohr model of atom:
Assumes that the angular momentum of electron is quantized
Uses Einstein’s photoelectric equation
Predicts continuous emission spectra for atoms
Predicts the same emission spectra for all types of atoms
Rutherford is the unit of:
Radioactivity
Energy
Photoelectric current
Magnetic field
When the mass of a sample of a radioactive substance decreases, the mean life of the sample:
Increases
Decreases
Remain unchanged
First decreases then increases
The phenomena of radioactivity is:
Exothermic change with increase or decrease with temperature
Increases on applied pressure
Nuclear process does not depend on external factors
None of these
Fusion reaction takes place, at high temperature because:
Nuclei break up at high temperature
Atoms get ionised at high temperature
Kinetic energy is high enough to overcome the coulomb repulsion between nuclei
Molecules break up at high temperature
When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom
Do not change for any type of radioactivity.
Change for α and ß radioactivity but not for γ-radioactivity.
Change for α-radioactivity but not for others.
Change for ß-radioactivity but not for others.
