3. Does a wire with a current running through it
have an electric field, a magnetic field, or
both? Explain how you know.

as net charge of a current carrying conductor is zero so no electric field is associated with at.

And

as moving charges give rise to magnetic field so magnetic field is associated with it

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.