Question 2 :
Calculate the number of neutrons in the remaining atom after emission of an alpha particle from <img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e79b58be89a3d2142170f5a' height='23' width='33' > atom<br>

Question 3 :
The half-life of 40K is 1.26 &times; 109 years and ratio of 40Ar/40K is 1.15 in the rock under study. Age of rock is-

Question 5 :
Match the radioisotopes with their application from the alternates given : <br>Radioisotopes &nbsp &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp Applications<br> &Iota;. Cobalt-60 &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbspP. Leukemia therapy <br>&Iota;&Iota;. Potassium-40 &nbsp&nbsp&nbsp&nbsp&nbspQ. Thyroid therapy <br>&Iota;&Iota;&Iota;. Iodine-123 &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbspR. Geological dating <br>&Iota;V. Phosphorus-32&nbsp&nbsp S. Cancer therapy <br>V. Carbon-14&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp T.Archeological dating<br> I II III IV V

Question 6 :
What should be the age of fossil for meaningful determination of its age ?

Question 11 :
Ra-226 decays with a half-life of 1.6 &times; 10³ years. By using definition of curie, Avogadro's number is-

Question 15 :
A G.M. counter is used to study the radioactive process of first-order. In the absence of radioactive substance A, it counts 3 disintegrations per second (dps). When A is placed in the G.M. counter, it records 23 dps at the start and 13 dps after 10 minutes. It records x dps after next 10 minutes and A has half-life period y minutes. x and y are :<br>

Question 17 :
In the chain reaction involving fission of <img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e79b5a0a2bddf222e0b05b2' height='24' width='33' >as <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e79b5a0e89a3d2142170f86' height='24' width='229' ><br>Neutrons and energy produced at the n^th step is-<br>

Question 18 :
The amount of {tex} \mathrm U - 235 {/tex} required per day to run a power house of capacity {tex}15 \mathrm{\ MW}{/tex}(efficiency of nuclear reactor {tex} 75 \% {/tex}. Assume energy liberated by fission of {tex}1 \mathrm {\ U } - 235{/tex} atom is {tex}200 \mathrm { MeV } {/tex}) is

Question 19 :
Naturally occurring boron consists of two isotopes whose atomic weights are 10.01 and 11.01. The atomic weight of natural boron is 10.81. Calculate the percentage of each isotope in natural boron<br>

Question 20 :
An atom has atomic mass 232 and atomic number 90. During the course of disintegration, it emits 2 &beta;-particles and few &alpha;-particles. The resultant atom has atomic mass 212 and atomic number 82. How many &alpha;-particles are emitted during this process<br>