One atom of iron contains 26 protons, 30 neutrons, and 26 electrons. Which of the following would be possible for another atom of iron? A. 25 protons, 30 neutrons, 26 electrons B. 26 protons, 28 neutrons, 26 electrons C. 25 protons, 30 neutrons, 27 electrons D. 27 protons, 30 neutrons, 26 electrons

B

Explanation:

An element is defined by the number of protons in the nucleus. If you change the number of protons in the nucleus, you change the element you're working with. If you change the number of neutrons, you change the isotope of the element without changing the element itself.

Iron has 26 protons. There are several possible isotopes of iron, but all have 26 protons; it's the number of neutrons that vary. Of the answer options provided, only B gives 26 protons, so only it can be another atom of iron.

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.