Can someone me? i think it might be (d) but i'm not i need the answer as soon as possible!

which best explains why a washing machine represents an open system?

(a) it has multiple cycles, such as wash or spin

(b) most washers can use a variety of laundry detergent brands

(c) the amount of wash in a load varies

(d) water and power come from external sources

im not to sure what it is

true

explanation:

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: