It's a chemical change since it cannot be reversed and the saliva releases a new substance
To solve this problem it is necessary to apply the concepts related to the capacitance in the disks, the difference of the potential and the load in the disc.
The capacitance can be expressed in terms of the Area, the permeability constant and the diameter:

Where,
= Permeability constant
A = Cross-sectional Area
d = Diameter
Potential difference between the two disks,
V = Ed
Where,
E = Electric field
d = diameter
Q = Charge on the disk equal to 
Through the value found and the expression given for capacitance and potential, we can define the electric charge as





Re-arranging the equation to find the diameter of the disks, the equation will be:

Replacing,


Therefore the diameter of the disks is 0.03m
Answer:
Sound wave is a longitudinal wave that propagates in a medium
Explanation:
<em>Part A:</em> (C) Sound wave is propagation of pressure fluctuations in a medium.
<em>Part B: </em>(C) Pressure fluctuations travel along the direction of propagation of the sound wave.
<em>Part C: </em>(A) Yes air play a role in the propagation of the human voice from one end of the lecture hall to the other.
F=mg=Gm1m2/r^2
g=Gm2/r^2
g=2Gm2/(2r)^2=2Gm2/4r^2=Gm2/2r^2
So since there is half times the gravity on this unknown planet that has twice earth's mass and twice it's radius, then the person can jump twice as high. 1.5*2= 3m high