If the density of the universe is less than a critical value, thenAnswers:1. it might eventually stop expanding.2. it might continue expanding forever.3. it could expand to a fixed size and remain.4. there's probably less dark matter than luminous.

2. it might continue expanding forever

Explanation:

If the ratio is greater than one, then the actual density of the Universe is greater than the critical density, and thus the Universe will eventually become closed and will ultimately end up collapsing in on itself. If the ratio is less than one, then the actual density is less than the critical density, and the Universe is open and expands forever in every direction

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: