Consider a solenoid of length l, n windings, and radius b (l is much longer than b). a current i is flowing through the wire. if the radius of the solenoid were doubled (becoming 2b), and all other quantities remained the same, the magnetic field inside the solenoid would a. would remain the same.

b. would become twice as strong.

c. would become one half as strong.

A.

Explanation:

The equation of Magnetic Field is given by

Where

Number of loops

I= current

constant of permeability of free space

As you can note, the magnetic field does not depend upon radius of the solenoid, therefore it would remain in same

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.