Answer:
A placebo refers to a substance or treatment that is often used in an experiment but does not have an actual medicinal or experimental benefit.
Explanation:
Any energy transformation involves the loss of some energy as B. Heat.
Answer:
Clumped distribution is the most common type of dispersion found in nature. In clumped distribution, the distance between neighboring individuals is minimized.
When person is observing destructive interference at 0.20 m distance from the equidistant position then we can say that path difference must be equal to half of the wavelength
now we will have

now we know that
y = 0.20 m
d = 2.4 m
L = 10 m
now here we have


now frequency of wave is given as


Beats.
When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats. The beat frequency is equal to the absolute value of the difference in frequency of the two waves.