Answer:
D.
Explanation:
To solve the exercise it is necessary to apply the concepts related to the Magnetic Field described by Faraday.
The magnetic field is given by the equation:

Where,
Permeability constant
d = diameter
I = Current
For the given problem we have a change in the diameter, twice that of the initial experiment, therefore we define that:


The ratio of change between the two is given by:




Therefore the correct answer is D.
Do you have a picture then I could determine 1 millimeter
Explanation:
Given that,
Radius R= 2.00
Charge = 6.88 μC
Inner radius = 4.00 cm
Outer radius = 5.00 cm
Charge = -2.96 μC
We need to calculate the electric field
Using formula of electric field

(a). For, r = 1.00 cm
Here, r<R
So, E = 0
The electric field does not exist inside the sphere.
(b). For, r = 3.00 cm
Here, r >R
The electric field is

Put the value into the formula


The electric field outside the solid conducting sphere and the direction is towards sphere.
(c). For, r = 4.50 cm
Here, r lies between R₁ and R₂.
So, E = 0
The electric field does not exist inside the conducting material
(d). For, r = 7.00 cm
The electric field is

Put the value into the formula


The electric field outside the solid conducting sphere and direction is away of solid sphere.
Hence, This is the required solution.
Aperture is measured in F-stops, in which the f-stops is the amount of light allowed to pass through the aperture, which simply put means that the smaller the aperture, the higher the f-stops. What it does is reduce the amount of light that reaches the film, so the higher the f-stops, the less light reaches the film.