1). Which of the following statements are correct? Total Internal reflection occurs: I. when the angle of incident is greater than the critical angle. II. if the light is travelling from less dense medium to denser medium. III. when the angle of incident is less than the critical angle. IV. if the light is travelling from denser medium to less dense medium. A. I and II B. I and IV C. II and III. D. III and IV.

0.19 m/s and 0.45 m/s

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.

no

explanation:

no i dont know how to solve this you should probably try to google the answer