Answer:
stars
those are stars in the galaxy
Answer:
60
Explanation:
According to the given question, the computation of minimum coating thickness is shown below:-
The condition for constructive interference is



Now we will put the values to the above formula to reach the answer

= 60
Therefore we simply applied the above formula to determine the minimum coating thickness
Answer:
v = 8.4 m/s
Explanation:
The question ays, "A longitudinal wave has a frequency of 200 Hz and a wavelength of 4.2m. What is the speed of the wave?".
Frequency of a wave, f = 200 Hz
Wavelength = 4.2 cm = 0.042 m
We need to find the speed of the wave. The formula for the speed of a wave is given by :

So, the speed of the wave is equal to 8.4 m/s.
The climate<span> was generally warmer and more humid than today, probably because of very active volcanism associated with unusually high rates of seafloor spreading.
</span><span>The first placental mammals appeared at the beginning of the Cretaceous. The Cretaceous saw the rise and extinction of the toothed birds, Hesperornis and Ichthyornis. The earliest fossils of birds resembling loons, grebes, cormorants, pelicans, flamingos, ibises, rails, and sandpipers were from the Cretaceous.</span>