Answer:
electrons
Explanation:
The total charge Q is the sum of the charge of the N electrons contained in the sphere:

charge of a electron
We solve to find N:

Correct question:
A solenoid of length 0.35 m and diameter 0.040 m carries a current of 5.0 A through its windings. If the magnetic field in the center of the solenoid is 2.8 x 10⁻² T, what is the number of turns per meter for this solenoid?
Answer:
the number of turns per meter for the solenoid is 4.5 x 10³ turns/m.
Explanation:
Given;
length of solenoid, L= 0.35 m
diameter of the solenoid, d = 0.04 m
current through the solenoid, I = 5.0 A
magnetic field in the center of the solenoid, 2.8 x 10⁻² T
The number of turns per meter for the solenoid is calculated as follows;

Therefore, the number of turns per meter for the solenoid is 4.5 x 10³ turns/m.
Answer:
a) 
b) 
c) 
Explanation:
the gravitational potential energy is given by:


The kinetic energy is given by:

the initial kinetic energy is zero because the motion started from rest, so:

applying the conservation of energy theorem:

The work done by the friction force is given by:

the angle of the force is 180 degrees because it's against the movement:

Answer: it is D. it is the only possible answer. use the process of elimination. which answers make sense?