An astronaut is stationary in space. which of these would have the greatest speed as observed by the astronaut? a: a ray of visible light b: a strong magnetic field c: a high speed electrical charge d: a longitudinal wave carrying sound

A: a ray of visible light  

Explanation:

Light is an electromagnetic radiation. It can travel through vacuum as well as medium. The speed of light is maximum in vacuum i.e. 3 × 10⁸ m/s. From experiments, scientists know that nothing can exceed the speed of the light i.e this speed of light is the upper limit and o particle or wave can travel with speed greater than this. Thus, a ray of visible light would have the greatest speed when observed by an astronaut.

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.