Refer to the Newsela article, "Doctoral Student Played a Big Part in First black Hole Photo." Part A Why did people believe it would be possible to view a black hole in space? A Black holes are too far away. B They are hidden by other objects in space. C Black holes absorb light. D They are too dangerous to approach. Part B Which evidence support the answer in part A? Select two correct answers. A "Since we need light to see, we cannot see black holes". B " Black holes can even pull light into themselves". C "Messier 87 is about 55 million light years from Earth". D "A galaxy is a system of millions or billions of stars".

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:

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