The half-life of radium is 1600 yr.  The fraction of a sample of radium that would remain

after 6400 yr 

(1) $\frac{1}{4}$                (2) $\frac{1}{2}$                 (3) $\frac{1}{8}$                   (4) $\frac{1}{16}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The count rate of a Geiger Muller counter for the radiation of a radioactive material of half-life 30 min decreases to 5 ${s}^{-1}$ after 2 h. The initial count rate was 

(1) 20 ${s}^{-1}$             (2) 25 ${s}^{-1}$             (3) 80 ${s}^{-1}$              (4) 625 ${s}^{-1}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An element A decays into element C by a two step process

$A\to B+{}_{2}H{e}^{4}\phantom{\rule{0ex}{0ex}}B\to C+2{e}^{-}$

then  

(1) A and C are isotopes

(2) A and C are isobars

(3) A and B are isotopes

(4) A and B are isobars

Concept Questions :-

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

Difficulty Level:

The radius R of a nuclear matter varies with A as

(1)                          (2)

(3)                              (4)

Concept Questions :-

Mass-energy equivalent
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Number of nuclei of a radioactive substance at time t = 0 are 2000 and 1800 at time t = 2s. Number of nuclei left after t = 6s is [MGIMS 2010]

(1) 1442               (2) 1554                 (3) 1652                 (4) 1458

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In a radioactive material the activity at time ${t}_{1}$ is ${R}_{1}$ and at a later time ${t}_{2}$, it is ${R}_{2}$. If the decay constant of the material is $\lambda$, then

(a) ${R}_{1}={R}_{2}{e}^{-\lambda \left({t}_{1}-{t}_{2}\right)}$                                    (b) ${R}_{1}={R}_{2}{e}^{\lambda \left({t}_{1}-{t}_{2}\right)}$

(c) ${R}_{1}={R}_{2}\left(\frac{{t}_{2}}{{t}_{1}}\right)$                                          (d) ${R}_{1}={R}_{2}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following are suitable for the fusion process ? 

(1) Light nuclei

(2) Heavy nuclei

(3) Elements lying in the middle of periodic table

(4) Elements lying in the middle of binding energy curve

Concept Questions :-

Nuclear binding energy
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An archeologist analyses the wood in a prehistoric structure and finds that ${\mathrm{C}}^{14}$ (Half - life=5700 years) to ${\mathrm{C}}^{12}$ is only one - fourth of that found in the cells buried plants. The age of the wood is about

1. 5700 yr

2. 2850 yr

3. 11,400 yr

4. 22,800 yr

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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
High Yielding Test Series + Question Bank - NEET 2020

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 :-