Answer:
i = 0.3326 L
Explanation:
A fixed string at both ends presents a phenomenon of standing waves, two waves with the same frequency that are added together. The expression to describe these waves is
2 L = n λ n = 1, 2, 3…
The first harmonic or leather for n = 1
Wave speed is related to wavelength and frequency
v = λ f
λ = v / f
Let's replace in the first equation
2 L = 1 (v / f₁)
For the shortest length L = L-l
2 (L- l) = 1 (v / f₂)
These two equations form our equation system, let's eliminate v
v = 2L f₁
v = 2 (L-l) f₂
2L f₁ = 2 (L-l) f₂
L- l = L f₁ / f₂
l = L - L f₁ / f₂
l = L (1- f₁ / f₂)
.
Let's calculate
l / L = (1- 309/463)
i / L = 0.3326
The electric force between two charge objects is calculated through the Coulomb's law.
F = kq₁q₂/d²
The value of k is 9.0 x 10^9 Nm²/C² and the charge of proton is 1.602 x10^-19 C. Substituting the known values from the given,
2.30x10^-26 = (9.0 x 10^9 Nm²/C²)(1.602 x10^-19C)²/d²
The value of d is equal to 0.10 m.
First,
where 
is density, 
is mass, and 
is volume. We can compute the volume of the roll:
When the roll is unfurled, the aluminum will be a rectangular box (a very thin one), so its volume will be the product of the given area and its thickness 
. Note that we're assuming the given area is not the actual total surface area of the aluminum box, but just the area of the largest face (i.e. the area of one side of the unrolled sheet of aluminum).
So we have
where 
is the given area, so
If we're taking significant digits into account, the volume we found would have been 
, in turn making the thickness 
.
In electronics, the SI unit for current is Ampere. It is the amount of charge in Coulombs per unit time. It is named after the father of electrodynamics, Andre-Marie Ampere. Also, the current can be easily determined through the Ohm's Law, which states that current is equal to volts divided by the resistance. The answer is letter D.
