Lasik eye surgery uses pulses of laser light to shave off tissue from the cornea, reshaping it. a typical lasik laser emits a 1.0-mm-diameter laser beam with a wavelength of 193 nm. each laser pulse lasts 20 ns and contains 2.0 mj of light energy.
part a: what is the power of one laser pulse?
part b: during the very brief time of the pulse, what is the intensity of the light wave?

a)     P = 1.0 10⁵ W, b)   I = 1.27 10¹¹ W / m²

Explanation:

a) the power is defined by the unit of time work

       P = W / t

Work is equal to the variation of energy

       P = E / t

Let's calculate

      P = 2.0 10⁻³ / 20 10⁻⁹

      P = 1.0 10⁵ W

b) intensity is defined as the ratio between power per area unit

      I = P / A

The area of a circle is

     A = π r²

     r = d / 2

     A = π (0.5 10⁻³)²

     A = 0.785 10⁻⁶ m²

     I = 1.0 10⁵ / 0.786 10⁻⁶

     I = 1.27 10¹¹ W / m²

the answer is 3.1 his answer is wrong mines is right

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.