Maybe, but she hasn't proved it yet. As another example, somebody may bring a jar of gas to your laboratory, and you test the gas in the jar and you find nitrogen atoms, oxygen atoms, argon atoms, and krypton atoms, and there isn't a single compound in it. The gas in the jar is a MIXTURE of gases . . . a mixture that we call "Air".
-- If the field were inclined to the surface, then it would have
some component parallel to the surface.
-- Then, since we're talking about a conductor, the charges
on the object would move in response to that component
of the field, until there was no longer any component of the
field trying to move them.
Answer:
The thickness of the foil is 0.017 mm.
Explanation:
Given that,
Weight = 7.5 oz = 212.6175 gm
Density = 2.70 g/cm³
Area of aluminium = 50 ft² = 46451.52 cm²
We need to calculate the thickness of the foil
Using formula of density



Where, A = area
t = thickness
m = mass
Put the value into the formula



Hence, The thickness of the foil is 0.017 mm.
Explanation:
The electrostatic forces are conservative forces!
The mainly property of the conservative fields is 
In spherical coordinates the field's expression is:

and the curl expression is:

to find the expression for the potential function associated:

The amplitude of wave-c is 1 meter.
The speed of all of the waves is (12meters/2sec)= 6 m/s.
The period of wave-a is 1/2 second.