In the nuclear reaction:  the term X will be :

(1) ${}_{5}B_{10}$                  (2) ${}_{5}B_{9}$

(3) ${}_{5}B_{11}$                  (4) ${}_{2}H{e}^{4}$

Concept Questions :-

Mass-energy equivalent
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Difficulty Level:

10 g of radioactive material of half-life 15 year is kept in store for 20 years. The disintegrated material mass is [Pb. PMT 2002]

(1) 12.5 g               (2) 10.5 g               (3) 6.03 g              (4) 4.03 g

Concept Questions :-

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Difficulty Level:

If a radioactive nucleus decays according to the following reaction

${}_{72}X_{180}\stackrel{\alpha }{\to }{X}_{1}\stackrel{\beta }{\to }{X}_{2}\stackrel{\alpha }{\to }{X}_{3}\stackrel{\gamma }{\to }{X}_{4}$

then the mass number and the atomic number of ${X}_{4}$ then the mass number and the atomic number of ${X}_{4}$ will be, respectively [MP PET 2002]

(1) 172, 70                     (2) 172, 69

(3) 172, 68                     (4) 171, 69

Concept Questions :-

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Difficulty Level:

Two radioactive materials ${X}_{1}$ and ${X}_{2}$ have decay constants 10$\lambda$ and $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of ${X}_{1}$ to that of ${X}_{2}$ will be $\frac{1}{e}$ after a time

(1)                      (2)

(3)                      (4)

Concept Questions :-

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Difficulty Level:

A radioactive material has mean-lives of 1620 yr and 520 yr for $\alpha$ and $\beta$-emission. The material decays by simultaneous $\alpha$ and $\beta$-emission. The time in which 1/4th of the material remains intact is

(a) 4675 yr                                 (b) 720 yr

(c) 545 yr                                   (d) 324 yr

Concept Questions :-

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Difficulty Level:

The radioactivity of an element becomes $\frac{1}{64}th$ of its original value in 60 seconds. Then the half value period is

(1) 5 sec              (2) 10 sec            (3) 20 sec            (4) 30 sec

Concept Questions :-

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Difficulty Level:

A nucleus of ${}_{84}{}^{210}Po$ originally at rest emits $\alpha$ particle with speed $\nu$. What will be the recoil speed of the daughter necleus. [DCE 2002]

(1) 4$\nu$ / 206                          (2) 4$\nu$ / 214

(3) $\nu$ / 206                            (4) $\nu$ / 214

Concept Questions :-

Types of decay
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Difficulty Level:

An atom of mass number 15 and atomic number 7 captures an $\alpha$-particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be

(1) 14 and 2                          (2) 15 and 3

(3) 16 and 4                          (4) 18 and 8

Concept Questions :-

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

Difficulty Level:

If radius of the ${}_{13}{}^{27}\mathrm{Al}$ nucleus is estimated to be 3.6 fermi then the radius of ${}_{52}{}^{125}Te$ nucleus be nearly

(a) 4 Fermi                                     (b) 5 Fermi

(c) 6 Fermi                                     (d) 8 Fermi

Concept Questions :-

Mass-energy equivalent
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Difficulty Level:

Solar energy is mainly caused due to [2003]

(1) fusion of protons during synthesis of heavier elements

(2) gravitational contraction

(3) burning of hydrogen in the oxygen

(4) fission of uranium present in the sun

Concept Questions :-

Mass-energy equivalent