3 small identical balls have charges -3×10^-12 ,8×10^-12 and 4×10^-12 find the charge

  3×10^-12 C  

Explanation:

The total of the three charges is ...

   (-3 +8 +4)×10^-12 C = 9×10^-12 C

Assuming the charge is equally distributed between the balls when they are brought in contact, the charge on each ball will be ...

  (9/3)×10^-12 C = 3×10^-12 C

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:

e

explanation:

there is no change in the electric potential energy as it is in rest on both conditions.