the electric charge remains at rest in a. static electricity, b. current electricity, c. none of these​

Option (a) is correct.

Explanation:

The electric charge is the inherent property of matter which appears due to the deficiency of charge or the excess number of electrons.

There are two types of charges, positive and negative.

When an object has deficiency of charge it becomes positive charge and when it gains some electrons, it becomes negative charge.

When the charge is in motion, it is called electric current and when the charge is at rest, it is called static current.

A charge at rest contributes the electric field only while the charge is in motion contributes the electric and magnetic field both.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary