The correct answer is “C” ultrasound. Hope this helps!
Radio waves are the longest
Physical changes: melting, evaporating, and condensation. This is a physical change.
Answer:
Explanation:
Point beneath you forms a beautiful iridescent green
refractive index of Gasoline 
Wavelength of Green light is 
Here light first traverse from air(n=1) to gasoline , it reflects from front surface of gasoline(n=1.38) so it suffers a phase change. After this light reflect from rear surface of gasoline and there is a decrease in refractive index(n=1.38 to n=1.33), so there is no phase change occurs .
For constructive interference

here t= thickness of gasoline film
n=refractive index
for 


False. C + O --> CO not CO2. Carbonmonoxide