Which part of an atom participates in the reaction shown below?
u235 + n → xe134 + sr100 + 2n
a) nuclei
b) protons
c) valence electrons
d) inner shell electrons

Option (A) is the correct answer.

Explanation:

A reaction in which nucleus of an atom and a subatomic particle like proton or neutron collide or when any two nuclei combine together then it results in the formation of a new nucleus that is different from its parent nuclei.

For example,

Here, nucleus of Uranium collides with a neutron resulting in formation of a Xenon and Strontium nucleus along with two neutrons.

Therefore, we can conclude that nuclei of an atom participates in the given  reaction.

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.