Answer:
The principle of a potentiometer is that the potential dropped across a segment of a wire of uniform cross-section carrying a constant current is directly proportional to its length. The potentiometer is a simple device used to measure the electrical potentials (or compare the e.m.f of a cell).
Explanation:
I hope it will help you
The answer is oil and water. If you want I could give you the reason too
If you move a magnet through a loop of wire, induction will happen. The more loops you make, the stronger the effect becomes.
Answer:
(a) 
(b) The charge inside the shell is placed at the center of the sphere and negatively charged.
Explanation:
Gauss’ Law can be used to determine the system.

This is the net charge inside the sphere which causes the Electric field at the surface of the shell. Since the E-field is constant over the shell, then this charge is at the center and negatively charged because the E-field is radially inward.
The negative charge at the center attracts the same amount of positive charge at the surface of the shell.
Answer:
B = 8.0487mT
Explanation:
To solve the exercise it is necessary to take into account the considerations of the Magnetic Force described by Faraday,
The magnetic force is given by the formula

Where,
B = Magnetic Field
I = Current
L = Length
Angle between the magnetic field and the velocity, for this case are perpendicular, then is 90 degrees
According to our data we have that
I = 16.4A
F = 0.132N/m
As we know our equation must be modificated to Force per length unit, that is

Replacing the values we have that

Solving for B,

