You buy a 75 W lightbulb in Europe, where electricity is delivered to homes at 240 V (meaning that the lightbulb is designed to deliver 75 W at 240 V). If you use this European lightbulb in the United States at 120 V (assuming its resistance does not change), how bright will it be relative to a U. S. lightbulb designed to deliver 75 W at 120 V. Hint: Assume that brightness is roughly proportional to power consumed.

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.