A nucleus of mass 218 amu in free state decays to emit an $\mathrm{\alpha }$-particle. Kinetic energy of the $\mathrm{\alpha }$-particle emitted is 6.7 MeV. The recoil energy (in MeV) of the daughter nucleus is

(a) 1.0              (b) 0.5
(c) 0.25            (d) 0.125

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

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${\mathrm{C}}^{14}$ has half life 5700 years. At the end of 11400 years, the actual amount left is

(a) 0.5 of original amount
(b) 0.25 of original amount
(c) 0.125 of original amount
(d) 0.0625 of original amount

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Mean life of a radioactive sample is 100 seconds. Then its half life (in minutes) is
(a) 0.693                (b) 1
(c) ${10}^{-4}$                 (d) 1.155

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

${}_{86}{}^{222}\mathrm{A}\to {}_{84}{}^{210}\mathrm{B}$. In this reaction how many $\mathrm{\alpha }$ and $\mathrm{\beta }$ particles are emitted
(a) 6$\mathrm{\alpha }$, 3$\mathrm{\beta }$          (b) 3$\mathrm{\alpha }$, 4$\mathrm{\beta }$
(c) 4$\mathrm{\alpha }$, 3$\mathrm{\beta }$          (d) 3$\mathrm{\alpha }$, 6$\mathrm{\beta }$

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

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(a) Exothermic change which increases or decreases with temperature
(b) Increases on applied pressure
(c) Nuclear process does not depend on external factors
(d) None of the above

Concept Questions :-

Difficulty Level:

If half life of radium is 77 days. Its decay constant in day will be
(a) $3×{10}^{-13}$/day            (b) $9×{10}^{-3}$/day
(c) $1×{10}^{-3}$/day              (d) $6×{10}^{-3}$/day

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In a sample of radioactive material, what fraction of the initial number of active nuclei will remain undisintegrated after half of a half-life of the sample
(a) $\frac{1}{4}$        (b) $\frac{1}{2\sqrt{2}}$
(c) $\frac{1}{\sqrt{2}}$     (d) $2\sqrt{2}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

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Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion 5 billion years ago. The other was created in a nuclear reactor 5 minutes ago. The probability of decay during the next time is
(a) Different for each nuclei
(b) Nuclei created in explosion decays first
(c) Nuclei created in the reactor decays first
(d) Independent of the time of creation

Concept Questions :-

Nuclear reactor

Difficulty Level:

An $\mathrm{\alpha }$-particle of 5 MeV energy strikes with a nucleus of uranium at stationary at an scattering angle of 180o. The nearest distance upto which $\mathrm{\alpha }$-particle reaches the nucleus will be of the order of
(a) 1 Å               (b)
(c)       (d)

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In a hypothetical Bohr hydrogen, the mass of the electron is doubled. The energy ${\mathrm{E}}_{0}$ and the radius ${\mathrm{r}}_{0}$ of the first orbit will be (${\mathrm{a}}_{0}$ is the Bohr radius)
(a)
(b)
(c)
(d)