Light energy emitted by stars is due to

(1) Breaking of nuclei                          (2) Joining of nuclei

(3) Burning of nuclei                            (4) Reflection of solar light

Concept Questions :-

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

Difficulty Level:

The constituents of atomic nuclei are believed to be 

(1) neutrons and protons

(2) protons only

(3) electrons and protons

(4) electrons, protons and neutrons

Concept Questions :-

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

Difficulty Level:

The half-life of radium is about 1600 yr. of 100 g of radium existing now, 25 g will remain unchanged after 

(1) 4800 yr         (2) 6400 yr           (3) 2400 yr           (4) 3200 yr

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High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The binding energy of deuteron is 2.2 MeV and that of ${}_{2}{}^{4}He$ is 28 MeV. If two deuterons are fused to form one ${}_{2}{}^{4}He$, then the energy released is 

(1) 25.8 MeV        (2) 23.6 MeV           (3) 19.2 MeV          (4) 30.2 MeV

Concept Questions :-

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

Difficulty Level:

Half-life of a radioactive substance is 12.5 h and its mass is 256 g. After what time, the amount of remaining substance is 1 g? 

(1) 75 h          (2) 100 h            (3) 125 h          (4) 150 h

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A radioactive substance disintegrates 1/64 of initial value in 60 s. The half-life of this substance is

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

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The nucleus ${}_{6}C_{12}$ absorbs an energetic neutron and emits a beta particle $\left({\beta }^{-}\right)$. The resulting nucleus is

(1) ${}_{7}N_{14}$          (2) ${}_{7}N_{13}$         (3) ${}_{5}B_{13}$             (4) ${}_{6}C_{13}$

Concept Questions :-

Mass-energy equivalent
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Difficulty Level:

If in a nuclear fusion  process, the masses of the fusion nuclei be  and the mass of the resultant nucleus be ${m}_{3}$, then 

(1) ${m}_{3}={m}_{1}+{m}_{2}$                     (2) ${m}_{3}=\left|{m}_{1}-{m}_{2}\right|$

(3) ${m}_{3}<\left({m}_{1}+{m}_{2}\right)$                  (4) ${m}_{3}>\left({m}_{1}+{m}_{2}\right)$

Concept Questions :-

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

Difficulty Level:

The nuclei of which one of the following pairs of nuclei are isotones? 

(1)                   (2)

(3)                     (4)

Concept Questions :-

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

Difficulty Level:

The counting rate observed from a radio active source at t = 0 second was 1600 counts per second and at t = 8 seconds it was 100 counts per second. The counting rate observed, as counts per second, at t = 6 seconds will be

(1) 400         (2) 300         (3) 200        (4) 150

Concept Questions :-