Answer:
A) Propagation of pressure fluctuations in a medium
B) air is the medium in which the wave is transported,
Explanation:
Part A.
A sound wave is a longitudinal oscillation of the molecules that forms in a material medium, they can be solid, liquid or gases, therefore the wave propagates in the same direction as the oscillation of the particles.
The most correct answer is:
* Propagation of pressure fluctuations in a medium
Part b
air is the medium in which the wave is transported, otherwise it cannot propagate
The frequency of a simple harmonic oscillator such as a spring-mass system is given by

where
k is the spring constant
m is the mass attached to the spring.
Re-arranging the formula, we get:

and since we know the constant of the spring:

and the frequency of oscillation:
f=1.00 Hz
we can find the value of the mass attached to it:
Answer:
0.22mm
Explanation:
A far sighted person is a person suffering from long sightedness i.e such individual can only see far distant object clearly but not near distant object. The defect is corrected using convex lens.
Since convex lens is used, the focal (f) length of the lens is positive and the image distance (v) is also positive.
Using the lens formula,
1/f = 1/u + 1/v
Where u is the object distance = 0.35mm
v = 0.6mm
1/f = 1/0.35+1/0.6
1/f = 2.86 + 1.67
1/f = 4.53
f = 1/4.53
f = 0.22mm
The focal length of the contact lenses will be 0.22mm